EP2414575A1

EP2414575A1 - Template-supported method of forming patterns of nanofibers in the electrospinning process and uses of said nanofibers

Info

Publication number: EP2414575A1
Application number: EP10712425A
Authority: EP
Inventors: Gyeong-Man Kim
Original assignee: Centro de Estudios Investigaciones Tecnicas CEIT
Current assignee: Centro de Estudios Investigaciones Tecnicas CEIT
Priority date: 2009-04-01
Filing date: 2010-03-31
Publication date: 2012-02-08
Also published as: DE102009015226A1; WO2010112564A1; US20120040581A1

Abstract

The invention relates to a method for producing two- and three-dimensionally structured, microporous and nanoporous nonwoven fabrics composed of nanofibers in any form with a very high degree of covering or depositing the fibers by a predefined conductive template as a collector and to the use of the nonwoven fabrics according to the invention. The three-dimensional structural formation can be influenced in a specific manner by the deposition density of the nanofibers produced by means of an electrospinning process, which deposition density can be set by means of the accumulation time of the fibers.

Description

Template-based patterning procedure of nanofibers in electrospinning

Methods and their applications

The invention relates to a method for the production of two- and three-dimensionally structured, consisting of nanofibers, micro- and nanoporous nonwovens in an arbitrary form with a very large degree of coverage or deposition of fibers through a predefined conductive template as a collector and the use of the webs according to the invention. The deposition density of the nanofibers produced by means of an electrospinning process over the accumulation time of the fibers allows the three-dimensional structure formation to be influenced in a targeted manner.

Modern synthetically produced polymeric fibers have many and varied innovative applications, such as multifunctional textiles with high breathability and weather resistance, as separation or storage media for gases, liquids or particle suspensions in process and safety technology, as optical fibers for telecommunications, as reinforcement components in super lightweight composite materials, in health care as well as in sports and leisure.

There are already numerous synthetic routes and manufacturing methods for producing one-dimensional structures consisting of different polymers within fibers, wires, rods, bands, spirals, rings and others. The polymer fibers often used for this purpose are traditionally made by melt, dry or wet-spinning processes, the typical fiber diameter being of the order of about 5 μm to 500 μm. However, the diameter of these fibers produced by conventional process techniques is limited downwards for process engineering reasons.

In recent years, however, based on nanotechnology, a significant contribution has been made to technological advances in the manufacture of ultra-thin fibers. Also to be classified here is the electrospinning process, which is a simple, fast and cost-effective method for producing nanofibers, in particular thin ones

Polymer fibers, with a diameter of up to a few nanometers, wherein in comparison to conventional mechanical methods, the stretching of the fibers takes place without contact by applying an external electric field.

In the electrospinning process, an electric field between a fine capillary nozzle, for example, the cannula of a syringe, and a collection electrode, such as a conductive plate, applied to counteract and eventually overcome the surface tension of the drop of polymer solution or melt exiting the capillary nozzle. In the event that the viscosity of the polymer solution or melt is within a certain optimum range, the droplets emerging from the capillary nozzle are deformed and, on reaching a critical electrical potential, drawn out into a thin thread, the so-called jet (FIG. 1).

This electrically charged jet, which now continuously draws out new polymer solution or melt from the capillary nozzle, is then accelerated in the electric field in the direction of the counter electrode. He is subjected to a very complex manner of bending instability (the so-called Whipping Mode), vigorously rotated and stretched.

The jet solidifies during its flight to the counter electrode by evaporation of the solvent or by cooling, so that within a few seconds continuous fibers are produced in looped form with typical diameters of a few nanometers to a few micrometers. These fibers are collected and processed on the nonwoven mat counter electrode (US 197550; Kenawy et al., Biomaterials 24: 907 (2003); Deitzel et al., Polymer, 42: 8163 (2001); Reneker et al., Nanotechnology 7: 216 (2000)).

In general, the jet drawn out of the capillary nozzle exerts a strong interaction between the electrical charges within the jets and the external electric field, which makes it difficult to clearly define the course of the jet. If a continuous plate made of a conductive material is used as the collecting electrode, a nonwoven fabric is obtained from nanofibers which lie dislocated on one another or next to each other on the collecting electrode (FIG. 2).

Due to their high length-to-thickness ratio and thus high specific surface area as well as their functionalization by a surface treatment or nanoparticles, the polymer nanofibers produced in the electrospinning process have fascinating possibilities for the generation of completely new "tailor-made" combinations of properties, which can not be achieved with conventional processes, such as eg for special textiles, as nanostructured reinforcement elements, for membrane-based separators, for sensors, for the immobilization of biological messengers, eg DNA, RNA, enzymes and pharmaceuticals, and in the fields of tissue engineering and regenerative medicine. In order to align the spun fibers with an order of magnitude, two approaches are generally known; On the one hand is the modification of the collector, such as a rotating drum, wheel-shaped bobbin or metal frame, on the other hand, the manipulation of the electric field, for example with the parallel conductive electrodes on a non-conductive collecting electrode or with several parallel to each other electric lenses perpendicular to the collecting electrode. (U.S. 4,689,186; R. Dersch et al., J. Polym., Part A: Pol. Chem., Vol. 41, 545-553.)

The fiber orientation is only one-dimensionally possible with the above-known methods, however, two-dimensional and three-dimensional structures can not be produced thereby. However, there is still a greater difficulty with these methods, namely, although the fibers thus produced are aligned more or less parallel side by side, the distances between the individual fibers can hardly control. The proportion of identically oriented fibers is referred to as degree of orientation and expressed in percent. In addition, these known methods for aligning nanofibers have numerous other disadvantages, including a complicated structure of the spinning plant and the need for multiple steps and thus a lot of time and cost.

US 26308509 B1 discloses an apparatus for producing textile fibers by electrospinning. Nanofibers are spun to linear structures in the form of yarns, so-called yarns, to increase their strength with textile fibers. These yarns can then be processed into two- or three-dimensional fabrics by means of textile treatment processes, such as weaving, braiding or knitting.

Furthermore, WO 2008/049250 A1 discloses a process for the production of microbicidal electrospun polymer fibers with polyethyleneimine nanoparticles for textile applications. This polymer fibers are spun with derivatized Polyethylenimin- nanoparticles and thus achieved an antibacterial or antifungal effect. The same effect is achieved by spinning polymer fibers with honey in encapsulated form as disclosed in WO 2008/049251 A1.

WO 2008/049397 A2 discloses a process for electrospinning water-soluble polymers into a water-insoluble polymer fiber. In this case oppositely charged polyelectrolytes are spun in aqueous solution by electrospinning to a water-insoluble polymer fiber.

DE 10 2007 040 762 A1 discloses an apparatus and a method for producing electrically conductive nanostructures by means of electrospinning. It will be electric conductive particles are spun together with the dope to form conductive line-like structures. In one embodiment, the electrically conductive nanostructures can be produced by post-treatment with conductive particles. Furthermore, it is disclosed that the deposition of the nanofiber produced on the collector takes place in a targeted orientation and high local precision. For this purpose, the spinning capillary and / or the substrate holder is designed to be movable and their relative movement to one another is controlled by a computer unit. The structures produced by this method, however, do not have the local precision required, for example, for use in microsystems technology. The precision is dependent on the relative movement, the precision of the

Drive unit and the optical detection unit which supplies the arithmetic unit with the information necessary for the relative movement. The results achieved thereby still have no reproducibility in the precision with regard to the local orientation of the deposited fibers. In addition, the disclosed method is time consuming and costly.

WO 2009/010443 A2 discloses a method for producing nano- and mesostructures by electrospinning colloidal dispersions containing at least one water-insoluble polymer. In this case, the water-insoluble polymer is spun in an aqueous solution to a fiber, wherein the glass transition temperature of the water-insoluble polymer is not more than 15 ⁹ C above to 15 ⁹ C below the process temperature. As a result, the use of solvents can be dispensed with as far as possible. However, the fibers and nonwovens produced by this method also have low precision in terms of deposition.

Due to complicated interactions between process parameters, such as viscosity, surface tension, conductivity, electric field strength, air resistance, and gravity, the process window of the electrospinning process is narrowly limited. In addition, the fibers in the nonwoven mat have all possible orientations, so that the use of these fleeces has hitherto been limited to special applications in which random fibers are also acceptable. Typical examples are applications in the filter industry.

For higher-quality applications, for example, in microelectronics and photonics, as well as in the specific tissue and organzüchtung, the defined generation of well-ordered one-, two- and three-dimensional structures in which the fibers are highly oriented, indispensable. The methods mentioned hitherto have the disadvantage that the shaping matrix must be preserved in order to align the fibers. It is therefore not possible to obtain by the known methods free web with respect to the handling for transfer for the further steps in order to produce the final high-quality products.

Also known is a method for generating patterns by electrospinning, using a predefined template (Zhang, D., et al., Adv. Mater., 2007, 19, 3664-3667). There, it is disclosed that the deposition of the nanofibers continues to show a random arrangement. Only when using elevations in the predefined collector better orientations can be achieved (Figure 3), wherein the

The degree of orientation depends on the distance of the surveys. If the distance is too great, a chaotic deposit continues to occur (compare, in particular, FIG. This effect is explained by the fact that Coloubm ^'s interaction is inversely proportional to the distance between capillary and collector. Since the Coulomb ^'rule interactions as a major driving force of the controlled deposition are therefore preferably takes place a separation in the range between the peaks (Fig.4). The proposed method works with the corresponding elevations in the collector to achieve a preferred orientation of the fibers.

As can be seen from Figs. 3 and 4, as well as the above description, although improved patterning is possible with the method thus disclosed, deposition of the jet in the gap of the template continues to occur, resulting in the desired large coverage or deposition level of the nanofibers contradicts.

It is therefore highly desirable to develop a process whereby not only can the fibers be controlled down to a particular position to enable the application specific structuring of the fibers to be spun, but also the nonwoven webs thus produced without affecting a substrate can be transferred.

The object of the present invention is therefore to specify a method and a device which makes it possible to produce two and three-dimensionally structured, nanofiber-based, microporous and nanoporous nonwovens in any desired shape with a very high degree of coverage or deposition of the fibers and thus opens up new applications for the micro- and nanoporous nonwovens produced.

The object is solved by the independent claims. advantageous Embodiments are given in the dependent claims.

According to the invention, the production of two and three-dimensionally structured, consisting of nanofibers, micro- and nanoporous nonwovens in any form with a very large coverage or Abscheidungsgrad the fibers by electrospinning using a predefined conductive template as a collector, which the to be generated structure. The deposition density of the nanofibers produced by means of an electrospinning process over the accumulation time of the fibers allows the three-dimensional structure formation to be influenced in a targeted manner.

In the method according to the invention, first a conductive pre-structured

Template placed as a collector (template) on a conventional conductive collecting electrode under the capillary and then grounded together with the collecting electrode. Since there is a strong interaction between the electrical charges inside the jet and the grounded stencil, the jet drawn out of the capillary nozzle can be deposited preferentially directly to the grounded stencil. In addition, the helical airline of the jet as it approaches the template is severely restricted by Coulombic interaction between it and the oppositely charged or grounded template only on the lattice towers within the template. In the intermediate areas of the lattice towers within the template, in which there is no conductive material (as in the holes of a screen), little or no fibers are deposited.

Thus, the control of the deposition position with the simultaneous patterning of jets can be made possible.

With the electrospinning process according to the invention, it is now possible, two- or three-dimensionally structured nonwovens made of polymeric fibers in any arbitrary

Form and with a very high distance order at a controllable thickness and with a very high coverage or Abscheidungsgrad the nanofibers by means of a template as a collector in a single step to produce. The process not only has the advantage that it allows for the first time anyway to produce multi-dimensional nonwovens of nanostructures, which are interconnected and thus a high

Have stability. In addition, it also requires significantly fewer process steps, making it both more cost-effective and faster in production. This makes it possible to open the required special nanostructured nonwovens made of nanofibres to a mass market. In order to produce the consistently ordered or structured nonwovens, first the deposition of the nanofibers on a specific position or a region within the collecting electrode should be precisely controlled.

With a method according to the invention, it is possible not only to place this deposition position in a controlled manner on a smaller surface within the collecting electrode. In addition, in a preferred embodiment, two- or three-dimensionally structured nonwoven webs of polymeric fibers in any desired shape and with a very long distance order of controllable thickness as well as a very high degree of coverage of the nanofibers by means of a template as a collector be produced in a single step.

Compared to other processes, which require several process steps and are thus time-consuming and costly, the inventive method is simpler, faster, more effective and cheaper.

The process according to the invention is based on a difference in the literature (D. Zhang et al., Adv. Mater., 2007, 19, 3664-3667 and D. Li, et al., Nano Lett. 2005, 5, 913-916). However, described method for the production of oriented nanofibers by electrospinning method (Figure 3) consists in the use of a predefined conductive template, whereby the production of well-defined structured nonwovens, which have a high degree of internal Abscheidungs- or Abscheidungsgrad is possible.

In contrast to the prior art, the deposition of spun fibers according to the invention directly on the template used with high local precision, when the predefined conductive template is used as a collecting electrode. The generated structures represent exactly the predefined conductive template.

Under the deposition or coverage of the nanofibers is in the sense of

This invention refers to a measure which indicates how much of the spun nanofibers are deposited directly on the template and not between the cavities. Preferably, the degree of deposition or coverage of the nanofibers is greater than 95% in a single operation.

The conductive template, which is on a common conductive collecting electrode, serves as a collector and is grounded together with the collecting electrode. The polymeric fibers are spun directly onto the template. As expected, the selection or preparation of the templates for the pattern formation plays a crucial role. They should be flat and well conductive. For the purposes of the invention, the term flat is understood to mean a two-dimensional template, for example in the form of a net, grid, etc., which in turn can itself be used for the desired pattern formation in a three-dimensional arrangement. In particular, unlike the above-described prior art, the template according to the invention has no protruding elevations or sharp points in the region of the conductive regions of the template, which are embodied, for example, as lattice masts.

The space between the conductive areas of the template, which are formed, for example, as lattice masts, etc., whereupon the fibers are to be deposited, should be empty, i. Cavities without fillings be.

Another important factor in patterning is the thickness of the template.

According to the invention, it is of the order of magnitude of 50 nm to 200 nm and 200 nm to 500 nm for the production of the microstructures imaged with nanofibers, with their

Distances between fiber bundles in dimension of 100 .mu.m to 500 .mu.m lie.

Preferred for nanofiber-imaged structures with the distances between

Fiber bristles of 500 .mu.m to 1000 .mu.m, the thickness of the template in the range of 500 .mu.m to 2000 .mu.m and especially for structures with the distances between fiber bundles of 500 nm to 1000 nm thickness of the template according to the invention should be in the range of 2 .mu.m to 200 .mu.m ,

In order to align the fibers on the order of magnitude, the chaotic course of the jet would first have to be controlled as precisely as possible. Since the electric charges are distributed along the jets occurring from the capillary, the progress of the jets can be controlled by the external manipulation of the electric field. Even with a slight variation in the profile of the electric field, an influence on the deposition of the jets is clearly noticeable.

On the basis of this principle, a pre-structured template, which generates an inhomogeneity within the electric field, is additionally applied on a continuous conductive plate as a conventional collecting electrode. Since the driving force for arranging the fibers is the electrostatic interaction between the electrically charged jet and the conductive template, this interaction can be specifically influenced by the shape of the templates. The fibers are preferably deposited in the region of the structured template within the collecting electrode, since the electric field strength has maximum values there. In addition, the helical flightline of the jet as it approaches the template is severely restricted by Coulombic interaction between it and the oppositely charged or grounded template only on the lattice towers within the template. In the intermediate areas of the lattice towers within the template, in which there is no conductive material (as in the holes of a screen), little or no fibers are deposited.

In one embodiment of the invention, the template is used directly as a collector so that the deposition of the jet strictly limits itself to the conductive areas of the lattice towers within the template. As a result, deposition is advantageously realized only in the area of the lattice masts and not in the intermediate area.

If the template is at least simply covered by the nanofiber over the entire width, the spinning process can be interrupted. Subsequently, the deposition layer of electrospun fiber for obtaining the freestanding nonwoven whose structure corresponds to that of the template is carefully separated from the template. The resultant fleece is available for use or possible after-treatment. After removal of the fleece, the template can be used immediately for further electrospinning operations.

According to the invention, the nanofibers are arranged as highly oriented fiber bundles in one or two directions in a single operation with a very high order of the fibers without further modification or redesign for the construction of the electrospinning process, depending on the pre-structured template.

When the fibers overlap on the template, the remaining charges are accumulated on the deposited fibers, with the other spun fibers being deposited, as in a continuous plate in the conventional electrospinning process, without restriction over the entire area of the collection electrode. Thus, thus, the fibers can be deposited randomly, i.e., without preferential orientation, between the lattice strands of lower density compared to the area outside the template.

In the electrospinning process according to the invention, the nanofibers pass through repeated formation and stacking in the form of a three-dimensional fleece (nonwoven mat) engulfed. The size and shape of the voids between the fibers in such webs can be easily controlled, so that applications as a filter material, as protective clothing, as packaging material or in erosion protection and as a carrier matrix in biomedical applications as well as the transport and the targeted release of pharmaceutical preparations are conceivable ,

The subject matter of this invention is also the production of the microporous and nanoporous structured, robust nonwovens from electrospun nanofibers arranged in oriented fiber bundles by means of a template.

The variety of the resulting morphological features of the nonwovens, which on the

Variation width of the structure of the template, the polymer materials used and the modification possibilities of freestanding nonwovens is based, opens up the process of the invention a great application potential.

In comparison with the previously known methods, the method according to the invention has the following advantages:

The structure of the electrospinning process has remained unchanged compared to conventional systems, with the exception of the additional template, which is arranged on a conventional collecting electrode (counter electrode).

The template can be easily and quickly pre-structured and customized for the specific applications.

The formed pattern of electrospun nanofibers corresponds to that of the template used.

The dimension of the fleeces is freely scalable.

As a result, the "up-scaling" is not limited by the dimensioning of the fleece.

To obtain the freestanding nonwovens, the structured deposition layers can be easily separated from the template.

The nonwovens thus obtained can be used to construct highly complicated structures.

In addition to its simplicity, convenience and high efficiency, the method according to the invention is also distinguished by the fact that the freestanding nonwovens produced are good can be transported and thus used for many applications.

The structured nonwovens according to the invention are characterized i.a. by the following special morphological and mechanical properties:

The nonwovens are highly micro- and nanoporous at the same time.

The fleeces can be produced individually with greater complexities, depending on the application.

In the resulting webs, the fibers are bonded together by adhesive forces, whereby the webs, along with the orientation of the fibers in the webs and the orientation of the microcrystallites, macromolecules, nanoparticles, etc. within the fibers themselves have reinforcing properties that facilitate the handling of the webs in the web Further processing significantly improved.

An extremely noteworthy feature in the process of the invention is that this technique allows the generation and alignment of spun fibers in situ during the electrospinning process. This makes it easier to manufacture nanofiber-based devices or components.

According to the invention, the template may consist of all conductive materials, e.g. in the form of wires and wire screens or perforated metal meshes, etc. of metallic materials or semiconductors or in the form of natural or man-made fibers impregnated with a conductive agent to increase their conductivity. The structural diversity of conventional

There are no limits to microfabrication techniques.

In one embodiment of the invention in FIG. 6, the lattice masts of the template, which are designed, for example, as wires, wire screens or perforated metal meshes, have a ratio of the width (b) of the lattice masts to their thickness (d) of> 1. This means that the lattice masts are wider than thick. The width (b) of the lattice masts in this case characterizes the expansion in the x and / or y direction, while the thickness (d) of the lattice towers in this case refers to the material thickness of the lattice masts in the z direction. One is particularly advantageous if the material in the z-direction is substantially smaller than in the x and / or y direction.

The method according to the invention enables highly ordered nanofiber webs to be produced in an application-specific manner according to the wishes of customers in order to better enclose their use. According to the invention, a polymer solution or melt is used for producing the structured nonwoven fabrics from nanofibers, suitable polymers being all known natural and synthetic polymers, mixtures of polymers with one another (polymer blends) and copolymers consisting of at least two different monomers, provided they are fusible and / or or at least be soluble in a solvent.

The polymer which can be used according to the invention can be prepared by processes known to the person skilled in the art or is commercially available.

Preference is given to polymers selected from the group consisting of polyesters, polyamides, polyimides, polyethers, polyolefins, polycarbonates, polyurethanes, natural polymers, polysaccharides, polylactides, polyglycosides, poly (alkyl) - methylstyrene, polymethacrylates, polyacrylonitriles, latices, polyalkylene oxides of ethylene oxide and / or propylene oxide and mixtures thereof.

The polymers or copolymers are particularly preferably selected from the group consisting of poly (p-xylylene); Polyvinylidene halides, polyesters such as

Polyethylene terephthalate, polybutylene terephthalate; polyether; Polyolefins such as polyethylene,

Polypropylene, poly (ethylene / propylene) (EPDM); polycarbonates; polyurethanes; natural

Polymers, e.g. Rubber; polycarboxylic acids; polysulfonic; sulfated

polysaccharides; polylactides; polyglycosides; polyamides; Homopolymers and copolymers of aromatic vinyl compounds such as poly (alkyl) styrenes), e.g. Polystyrenes, poly-alpha-methylstyrenes; Polyacrylonitriles, polymethacrylonitriles; polyacrylamides; polyimides;

Polyphenylene; polysilanes; polysiloxanes; polybenzimidazoles; polybenzothiazoles;

polyoxazoles; polysulfides; polyester; Polyarylene-vinylenes; polyether ketones;

Polyurethanes, polysulfones, inorganic-organic hybrid polymers such as ORMOCER® from the Fraunhofer Society for the Advancement of Applied Research e.V. Munich;

silicones; wholly aromatic copolyesters; Poly (alkyl) acrylates; Poly (alkyl) methacrylates;

polyhydroxyethylmethacrylates; Polyvinyl acetates, polyvinyl butyrates; polyisoprene; synthetic rubbers such as chlorobutadiene rubbers, e.g. Neoprene® from DuPont;

Nitrile-butadiene rubbers, e.g. Buna N®; polybutadiene; polytetrafluoroethylene; modified and unmodified celluloses, homopolymers and copolymers of alpha-olefins and

Copolymers composed of two or more monomer units forming the above-mentioned polymers; Polyvinyl alcohols, polyalkylene oxides, e.g. Polyethylene oxides;

Poly-N-vinylpyrrolidone; hydroxymethylcelluloses; maleic; alginates; Polysaccharides such as chitosans, etc .; Proteins such as collagens, gelatin their homo- or copolymers and mixtures thereof. In one embodiment of the method according to the invention, a solution of the abovementioned polymers is used for the production of nanofibers, it being possible for this solution to comprise all solvents or mixtures of solvents. In general, a solvent is used, selected from the group consisting of chlorinated solvents, for example dichloromethane or chloroform, acetone, ethers, for example diethyl ether, methyl tert-butyl ether, hydrocarbons having less than 10 carbon atoms, for example n-pentane, n Hexane, cyclohexane, heptane, octane, dimethylsulfoxide (DMSO), N-methylpyrrolidinone (NMP), dimethylformamide (DMF), formic acid, water, liquid sulfur dioxide, liquid ammonia and mixtures thereof. Preference is given to using as solvent one of the group consisting of dichloromethane, acetone, formic acid and mixtures thereof.

In one embodiment, the mixing for the spinnable polymer solutions is carried out with stirring, under the action of ultrasound or under the action of heat. The concentration of the at least one polymer in the solution is generally at least 0.1 wt .-%, preferably 1 to 30 wt .-%, particularly preferably 2 to 20 wt .-%.

For the purposes of the invention, in addition to the polymer solutions, it is also possible to use corresponding polymer melts, provided that they are present in liquid form. Hereinafter, the term polymer solution is used equally synonymous with polymers which have been dissolved in solvents or converted by melting into liquid form.

A major obstacle in the production of devices or components with the help of nanotechnology is an "up-scaling" of the highly ordered structural unit.The movement or displacement of the template in the xy direction makes both the homogenization of the layer thickness of fleece and the expansion The thickness of the nonwovens can be determined by the deposition time and the

Shape of the nonwovens can be adjusted very precisely by the structure of the template.

Furthermore, it is easily possible to apply an arbitrary number of additional layers consisting of different polymeric materials by means of electrospinning to a nonwoven still on the template, thereby enabling the production of three-dimensionally structured multilayer nonwovens.

The minimum structure sizes of the nonwovens correspond to the diameter of the nanofibers, which range from a few nanometers to a few micrometers, depending on the polymer and the process conditions of the electrospinning process. The coverage or degree of deposition of the nanofibers in the method according to the invention is dependent on the material and template in the range between 60 and 100%, which causes an increased mechanical strength of the nonwovens.

The variety of possible combinations and functionalizations of materials, the possibilities of manipulating fiber structures, the application-specific modification with color pigments, catalysts or nanoparticles of metals, semiconductors or ceramics as well as the equipment with wound healing drugs, enzymes or antiviral or antibacterial agents, biological messengers ( such as DNA, RNA and proteins) and the thus adjustable property combinations allow a fascinating wealth of applications that are not achievable with conventional methods.

In one embodiment of the invention, prior to spinning into the polymer solutions or melts, all known nanoparticles having different dimensionalities can be mixed in easily and then applied to the template together with the polymer as nanocomposite nanofibers. By incorporating nanoparticles, the advantages of nonwoven structuring and fiber orientation within the nonwovens can be combined with the tailored functionalities of the nanoparticles, resulting in numerous application fields.

In a further embodiment of the invention, metals and / or semiconductors may be mixed in as nanoparticles before spinning into the polymer solutions or melts with different dimensionalities and then applied to the template together with the polymer. As a result, conductive nanofibers or nanofiber structures can be produced.

In a further embodiment of the invention, pharmaceutical active substances can be mixed in as nanoparticles before spinning into the polymer solutions or melts with different dimensionalities and then applied to the template together with the polymer.

The freestanding nonwoven webs produced by the method according to the invention can be selectively modified by means of different chemical and / or physical processes according to the particular application (irradiation with UV or gamma rays, plasma treatment, impregnation, eg with pharmaceutical agents or catalytic precursors, etc.). The structures of the invention may further surface modification with cryogenic plasma or chemical reagents, such as aqueous hydroxide solution, inorganic acids, acyl anhydrides, or halides or others depending on the surface functionality with silanes, isocyanates, organic acyl halides or anhydrides, alcohols, aldehydes or alkylating Be subjected to chemicals with their corresponding Katalyten. By a surface modification, for example by coating or irradiation with high-energy radiation, the nonwovens can obtain a more hydrophilic or more hydrophobic surface, which is advantageous for use in the biological or biomedical field.

In a further embodiment of the invention, to increase the

Biocompatibility the surface of the nanofibers or nonwovens according to the invention by suitable methods such as coating, adsorption, self-structuring, graft copolymerization, etc. modified.

In one embodiment of the invention, ceramic nanofibers are made by the electrospinning process of the invention from a mixture of the polymer solution with a wide variety of suitable ceramic precursors. The ceramic precursors are preferably selected from the group consisting of Al ₂ O ₃ , CuO, NiO, TiO ₂ , SiO ₂ , V ₂ O ₅ , ZnO, Co ₃ O ₄ Nb ₂ O ₅ , MoO ₃ and MgTiO ₃ .

An overview of the hitherto known processes for producing the ceramic nanofibers and wires is disclosed in the literature (R. Ramaseshan et al., Journal of

Applied Physics 102, 11111 (2007), Adv. Mater. 2004, 16, No. 14, pages 1 151 -1 169).

In a further embodiment of the invention, the sheathing of the fibers takes place, for example, by vapor deposition, sputtering, spin coating, dip coating, spraying, plasma deposition, sol-gel methods or atomic layer deposition. Preferably, the cladding is carried out by vapor deposition or atomic layer deposition.

In a further embodiment, the polymer is removed after covering the nanofibers. Suitable methods for removing the polymer are, for example, thermal, chemical, radiation-induced, biological, photochemical methods, as well as methods by means of plasma, ultrasound, hydrolysis or by extraction with a

Solvent. Depending on the polymer material, the removal is preferably carried out at 10-900 ° C and 0.001 mbar to 1 bar. The removal can take place completely or in a proportion of at least 70%, preferably at least 80%, particularly preferably at least 99%. The high specific surface area is associated with a considerable capacity for the adhesion or detachment of functional groups, adsorption or absorption of molecules, ions, catalytically active substances and various nanoscale particles. In addition, individual fibers and the resulting fiber mats (nonwovens) are particularly well suited as reinforcing components within a polymer matrix for producing ultralight polymer composites due to their high specific surface areas in combination with the high aspect ratio, high flexibility and strength.

In the electrospinning process according to the invention, the nanofibers are formed by repeated application and stacking in the form of a three-dimensional nonwoven

(Nonwoven Mat) devoured. The size and shape of the voids between the fibers in such webs can be easily controlled so that they can be used as filter material, protective clothing, packaging material, erosion protection and carrier matrix in biomedical applications, as well as for the transport and targeted release of pharmaceutically active substances are conceivable.

The inventive method presented here is a pioneering technology for the production of controllable "patterning" of the electrospun fibers only in a working cut, which allows the time-saving applicability of this method.

In one embodiment of the invention, the structured nonwovens according to the invention are used as scaffolds in the field of "tissue engineering" or "regenerative medicine." These carrier frameworks are used in in vitro methods for the production of replacement tissues and organs for the purpose of improving or improving the tissue Maintaining the function of diseased or destroyed tissue The aim is to support a tissue defect only as far as necessary in healing, so that ultimately healthy and functional endogenous tissue is reborn.

The support materials must meet high standards: they should be biocompatible, sterile, either long-term stable or biodegradable and flexible depending on the application. In addition, they must be porous, so that cells can migrate into it while still strong enough not to tear at the first mechanical stress.

The highly ordered carrier frameworks produced in different geometries and sizes by the process according to the invention not only fulfill the task of providing the cells and the extracellular matrix with a three-dimensional template for their growth but also provide sufficient mechanical stability to allow convenient spatial organization of the tissue to be cultured and unobstructed matrix deposition.

Due to the high porosity of the nonwovens according to the invention with cavities (inter-fiber cavities) in the nanometer and micrometer range, the cells to be cultivated colonize the nonwovens in a short time and at high density (controlling cell growth). Nutrients can be easily transported to the cells and metabolic wastes removed.

The bioresorbable polymers are due to the different degradation mechanisms and the associated adjustable degradation times increased use in medicine. If the framework materials consist of such bioresorbable polymers, the generated cell or tissue association can be grafted together with the framework. The polymer materials dissolve slowly due to their biodegradability in the body, whereby the remaining endogenous tissue gradually takes over the function of the tissue or organ, without a renewed surgical intervention is necessary.

In addition, during the electrospinning process or by subsequent modification of the webs, the fibers may be treated with various types of messengers, e.g. Growth factors (attracting cells, stimulating the growth of added cells), or drugs, e.g. Antibiotics and antiseptics are equipped with the aim of targeted release of pharmaceutical preparations in the organism after implantation.

The term tissue here means an accumulation of cells of an individual organism, which are optimally specialized in the execution of a specific task. In particular, mechanically robust, contractible muscles or cardiovascular tissues are of higher density aligned cell morphology. to

In order to grow such functional tissues, it is desirable that the scaffolds should not only support cell-to-cell interaction but also provide cell-mimicking structures of original tissues.

It has been shown in the literature that the cultured cells on the scaffolds, with the fibers one-dimensionally aligned, preferentially proliferate in the fiber direction (CY Xu, et al., Biomaterials 25: 877 (2004); CH Lee). et al., Biomaterials 26: 1261 (2005)). The nonwovens produced with the invention meet the requirements for one- and two-dimensional structures for the production of specifically such types of fabric. They not only provide mimicking scaffolds for nanoscale, natural extracellular matrices, but also provide a necessary defining architecture for guiding cell growth and development. The achievable alignment of the cells in controlled one-, two- and three-dimensional architecture has a crucial importance for differentiation, proliferation and functional longevity (lifetime) of the cell.

The ability of the method of the present invention to produce high-level, high-level fibers provides the potential for clinical studies of cellular behavior, such as cell proliferation. Gene expression and interaction of cells, industrial toxicology, etc., depending on fiber orientation.

In a further embodiment of the invention, the structured nonwovens according to the invention are used for the production of special patches for haemostasis.

Ideal dressings should be used in addition to their support function and the avoidance of

Penetration and Vermehrens of microorganisms, especially the moist and thus promote healing physiological microclimate maintained. This also includes ensuring gas and water vapor permeability since undisturbed epithelization requires a sufficient amount of dissolved oxygen in the wound exudate. In addition, a scab formation is to be prevented, which protects against external influences, but at the same time binds the secretion and thus hampers the migration of the newly formed cells. Special versions also reduce scarring.

Based on the method according to the invention, a new generation of wound plasters consisting of biocompatible and absorbable nanofibers is developed, whereby wound healing is considerably accelerated.

A special feature of electrospun fibers is their nanoporous surface structure, whose nanopores effectively act as a sponge for wound exudate, effectively closing up germs and tissue debris. But they also cause the maintenance of a healing promoting moist wound environment.

In a further embodiment of the invention, the nanofibers with various pharmaceutical substances, such as growth factors (attraction of skin cells, stimulation or acceleration of the growth of the added skin cells) or drugs (antibiotics, antiseptics, especially pain and Blutemmungsmedikamente, which are suitable for topical application, loaded to create optimal conditions for rapid wound healing.

In a further embodiment of the invention, the wound patch loaded with messenger substances gradually biodegrades during the healing process, as a result of which the painful dressing change, which often partially removes newly formed tissue again, can be dispensed with. In addition, depending on the requirements of the patient, the patch may deliver one or more drugs to the wound site within a given period of time.

With the technology according to the invention, the wound plasters can be produced both in a patient-specific manner in various sizes and shapes and can also be equipped with specific active ingredients (diabetes, arterial occlusive disease, chronic venous insufficiency, etc.). The wound plasters thus make a time-saving, easy to perform and cost-effective wound healing therapy.

In a further embodiment of the invention, the nanofibers produced according to the invention are used as support tubes for the regeneration of blood vessels, esophagus and nerves. As a result, for example, vascular lesions or aneurysms, which have hitherto been treated by coiling (endovascular aneurysm occlusion), can be successfully treated. The use of the support tubes according to the invention as stents is also provided. In a further development of this embodiment, by loading the support tubes according to the invention with pharmaceutically active substances, improved healing by their release in situ is possible. This could also reduce the required doses of the applied substances by avoiding systemic application.

In a further embodiment, the support tubes produced according to the invention are made of biodegradable substances. As a result, only a temporary foreign body incorporation takes place in the corresponding tissue section, whereby possible resulting rejection reactions are avoided.

In a further embodiment of the invention, the biodegradable support tubes according to the invention are loaded with pharmaceutically active substances.

Due to biodegradability, such constructions perform a depot function, whereby the active ingredients are released over time to the surrounding tissue and at the same time the depot itself is subject to degradation. As a result, minimally invasive techniques can be used to produce drug depots that can be used specifically at the site of action, without necessitating a subsequent removal.

In a further embodiment of the invention, the nonwovens of nanofibers produced according to the invention are used for surface modification of implants. Through appropriate functionalization of the surface, the immune response and the resulting risk of implant rejection can be reduced or minimized. By appropriate coating with proteins, such as extracellular matrix proteins, signaling proteins, cytokines, etc., a colonization of the body's own cells on the implant is possible.

In a further embodiment of the invention, an antimicrobial coating of the implants takes place by the application of biocompatible and biofunctional electrospun nanofibers to the implant. As a result, possible inflammations are prevented by germs. Typical examples of this are the nonwovens embedded with TiO ₂ as a photocatalytic coating for the applications of self-sterilization and biofiltration. On the other hand, use of MgO and ZnO nanoparticles as effective disinfectants in dyes for inner walls.

In one embodiment of the invention, various metal-containing inorganic materials are used as antibacterial agents in the fibers; such as. Silver, copper, zinc and other antibacterial metals as inorganic disinfectants. The release of the antibacterial agents from the nonwovens produced by the process according to the invention to the environment takes place continuously over a relatively long period of time. Relative to other conventional administration methods, the release of disinfectant by means of the nonwoven produced by the process according to the invention is superior in terms of safety, durability and heat resistance.

In a further embodiment of the invention, the nonwovens made from nanofibers according to the invention are produced as porous membranes and used as temporary skin substitutes. It is advantageous if the webs according to the invention are made of biodegradable substances.

In a further embodiment of the invention, the nonwovens produced according to the invention are used as support tubes in the regeneration of nerves. In this case, the nonwovens according to the invention are coated with suitable signal substances, whereby the proliferation of the nerve cells along the nonwoven is promoted. These coated nonwovens are then used in the area of the interrupted nerve connection. By applied to the fleece signal substances are the adjacent Nerve cells are stimulated to proliferate in the direction of the fleece. As a result, new neuronal connections are formed, which reconnects the interrupted nerve conduction.

In one embodiment of the invention, the nonwovens structured according to the invention are used for producing ultralight polymer composites.

The structured nonwovens according to the invention, because of their high specific surface areas in combination with the high aspect ratio, the high flexibility and strength of the fibers, are particularly suitable as reinforcing components within a polymer matrix for the production of ultralight polymer composites.

In one embodiment of the invention for the production of

Polymer nanocomposites compacts the nonwovens structured according to the invention by means of a "hot compaction" process under defined process conditions (pressure, temperature) without destroying the nonwoven structuring and the orientation.

The nonwovens reinforced polymer composites produced by the method according to the invention make it possible to combine the material properties to measure; on the one hand a sufficient voltage transfer over the matrix-fiber interface is ensured, on the other hand, however, the damage tolerance is increased (crack stop, crack diversion).

Variations of the properties result from a change in the nonwoven morphology, ie the thickness, distribution and orientation of the fibers.

Due to the size of the fibers, the compacted webs show a stronger polymer-fiber interaction in the interfacial layer of the fibers to the matrix. With such surface consolidations, the corrosion resistance, the fatigue strength and the impact resistance, ie essential properties for the use of the layers, can be improved. An increased micro- and nano-porosity of the nonwoven also provides improved adhesion.

Unlike fiberglass composites, these novel polymer-nanofiber composites meet the requirements of a balanced property profile (e.g., strength, stiffness, and toughness) with low specific gravity, opening up a wide range of applications.

Very important for the use of the nonwovens according to the invention are also the optical properties of the resulting nanocomposites, such as the unmodified Matrix materials comparable high transparency of the composite. The transparency is due to the fact that the diameter of the nanofibers is considerably smaller than the wavelength of the visible light.

The ultra-thin fibers with diameters up to a few nanometers can still be easily mixed with different nanofillers, such. modify one-dimensional carbon nanotubes, two-dimensional phyllosilicates, and three-dimensional nanoparticles. In contrast, the challenge with conventional methods is to homogeneously disperse the nanoparticles in the fibers while avoiding agglomerates and thus localizing stress concentrations under load in the matrix material.

Due to the extremely high shear force during the electrospinning process, the originally random nanoparticles with a nearly parallel arrangement are arranged in the nanofibers. As a result, an improvement of certain properties (strength, diffusion barrier, flame retardancy) is made possible.

Usually, the proportion of nanoparticles in compact nanocomposites is 0.1-5 wt .-% (weight percent) and is thus very low compared to conventional mineral fillers. The weight fraction of nanoparticles in nanofibers is often well below 0.001 wt .-%.

In one embodiment of the invention, the nonwovens according to the invention are modified with nano-layer silicates. These with nano-layer silicates, e.g. Montmorillonite, hectorite and saponite, modified polymers have improved properties in terms of UV and heat resistance, reduced flammability and gas permeability and increased biodegradability in the case of biodegradable polymers.

In another embodiment of the invention, carbon nanotubes (CNTs) are dispersed in the polymers. Composites formed by the dispersion of carbon nanotubes (CNTs) in polymers are characterized by higher mechanical strength and thermal and electrical conductivity.

In a further embodiment of the invention, the nonwovens according to the invention are used as filter media.

In general, the electrospun webs have the consistency of typical porous membranes with their porosity of the order of 60 to 80%. Due to the high pore density with adjustable pore size (micro- and nanoporosity) Applications arise as a filter material (liquid and gas filtration, molecular and bacterial filtration, clean room technology, air conditioning).

As a result of the production method according to the invention, the membranes have special surface characteristics as a result of which physically and / or chemically active substances are immobilized within the fibrous structures. In order to be able to safely separate even small particles, the pores should be as small as possible, with a small distribution width of the pore diameter. Since the

Throughflow resistance should be as small as possible, a large porosity or a large flow area is preferable.

Due to the large surface area of the nanofibers, the nonwovens according to the invention have a high absorption capacity for adhering dirt particles with high permeability of the substance to be fixed. So have the advantage of a significantly lower total pressure loss at the same or higher absorption capacity and thus extend the service life of the filter compared to conventional fine-pored filter media. The extension of the service life is a factor that reduces the filter-related operating costs.

The probability of a micro-particle being held in the air flow by a nanofiber increases simultaneously with the number of nanofibers. In the nonwovens according to the invention, a high proportion of nanofibers, with at the same time very high porosities in the filter media, almost completely retains even the finest particles and fine dust.

The fine, fabric-like network structure with very small fiber gaps allows the nonwovens according to the invention to retain particles with a very high degree of separation, but to allow liquids and / or gases to pass through unhindered.

Thus, the nonwovens according to the invention are distinguished as filter media by an excellent balance between separation efficiency, air permeability and service life.

In order to ensure a sufficiently long service life, apart from fulfilling the separation function, the mechanical use of nanofibers in filters also involves different mechanical and physical aspects, such as modulus of elasticity,

Tensile strength, marginal bending stress, abrasion resistance, moisture absorption, cold flow, temperature resistance, thermal conductivity, electrical resistance, light resistance, weight, etc. must be taken into account. While the nanofibers distributed randomly between the highly ordered regions of the nonwovens are crucial for the filtration of very small particles, the lattice-oriented nanofibers contribute to the tensile strength of the filter medium, depending on the load. The structure-forming nanofibers also increase the crack resistance of the filter medium.

In this way, high separation efficiency is associated with higher permeability and with so great mechanical stability of the medium.

The webs according to the invention are used in demanding industrial filtration under the most difficult conditions as well as in special filters for heavy-duty vehicles, ie in applications in which an extremely low filter weight with a high permeability and / or large specific filter surface is required.

By means of the method according to the invention, the structuring of the nonwoven fabric can be controlled, so that webs adapted exactly to the requirements of the concrete separation processes are constructed.

To modify the surface properties, i. to change the use properties or the electrical conductivity, the nonwovens can also be provided with finishes, these coatings have only a limited fatigue strength.

In addition, different nonwovens can compact together without their

Destroy structure. For example, it makes sense to combine a mechanically less stable superfine fleece of small thickness to optimize the deposition with a mechanically robust carrier fleece to optimize the load capacity with each other.

By means of backwashing, spraying, applying ultrasound, leaching u. a. the blockage of a filter medium can be counteracted. The simpler the pore structure of the filter medium, the easier it is to avoid its permanent blockage.

The main advantage of this technology, in addition to the price advantage, is to be able to develop and manufacture customized products where the gradient between coarse and fine porosity is freely adjustable over a wide range.

The advantages of this technology are a significantly improved filter efficiency, a significantly improved service life, a low production cost and thus low costs adjustable gradient of coarse fibers and nanofibres, protection of the integrated nanofibers against mechanical damage and a low use of raw materials.

In a further embodiment of the invention, the nanofibers and / or nonwovens produced according to the invention are used for coating and / or as a component of textiles.

It is common practice to produce specific properties of synthetic fibers directly through the manufacturing process, since technical textiles must meet special requirements according to their various applications. The properties of the fibers in the webs according to the invention can be adjusted as required.

The peculiarity of the nonwovens according to the invention is based on their very large surface area. In addition, due to the well-defined orientation of nanofibers, they have increased tensile strength and reduced gas permeability, making them suitable for very diverse applications.

By introducing a wide variety of additives (for example with color pigments,

Latex droplets, with catalysts, enzymes, pharmaceuticals, semiconductors or metallic nanoparticles, etc.) in or on the fibers, new textile finishes are to be developed which lead to the generation of new textile products with significantly improved or previously unrepresentable properties or combinations of functions ( antibacterial, self-cleaning, conductive, anti-static, protection against ultraviolet radiation (UV), flame retardance, thermal insulation and much more) based on the effects of nanostructures.

In one embodiment, the nonwovens according to the invention find applications within the textile industry as special textiles with excellent heat insulation properties, as protective clothing to minimize air impedance, textile materials with a high adhesive efficiency for nanoparticles and antibiochemical gases and for photo or thermochromatic clothing by incorporation of color pigments in the nanofibers.

When the fibers within a textile are metallized or their conductivity increased, for example, body functions such as heart rate, temperature or

Blood pressure can be measured. With a nanometer-thin metal coating this is guaranteed - while at the same time high wearing comfort. A fundamentally simple possibility for increasing the electrical conductivity of nanofibers is the incorporation of conductive materials in the form of finely divided particles into the polymer matrix.

In one embodiment of the invention, conductive materials in the form of finely divided particles are incorporated into the polymer matrix for protection against electrostatic discharges in protective work clothing. Protection against electrostatic discharges is indispensable in many areas of occupational safety. The result is metallic, nanometer-thin layers deposited in the process that increase the conductivity of the polymers by several orders of magnitude. The conductive materials used are metals (such as gold, silver, aluminum, iron, copper, nickel), carbon (in the form of carbon black, graphite or currently carbon nanotubes) or conductive polymers (polyaniline, polypyrrole, polyethylenedioxythiophene). Thus, fibers are used as electrical conductors in the field of antistatic agents.

In a further embodiment of the invention, the silver coatings or incorporated silver nanoparticles deposited on the nanofibers have an antibacterial effect. Silver-sheathed fibers in special underwear for atopic dermatitis sufferers B. for an improvement of the clinical picture. The silver-coated nonwovens can continue to be used in health care to combat the spread of antibiotic-resistant bacterial strains. Surgical drapes and other textile utensils prevent the spread of infections thanks to silver equipment, as they kill the bacteria within an hour.

In a further embodiment of the invention, the textiles according to the invention for medical applications and in the leisure / wellness with active or perfumes (cyclodextrins or Oiodosobenzoesäure and various types of deodorants) are spun. Nanoscale depot structures are able to bind odor molecules and release them again on the next wash.

In a further embodiment of the invention, the removal of bacteria can also be used to combat odor in sportswear, since the sweat odor produced by the bacteria. Since the pores in a nonwoven fabric according to the invention are substantially smaller than a water droplet, the nonwoven fabric is very dense against water and wind. Body moisture, however, is transmitted as water vapor. The nonwovens according to the invention are thus breathable and thus allow the removal (diffusion) of the evaporated sweat, which is enormously important for the temperature regulation of the body. Sweat athletes overly at high loads, Afterwards they feel a cooling of the body, which is perceived as unpleasant. This so-called "post exercise chill effect" can be prevented by nanostructuring of the fibers, because their capillary action ensures rapid removal of perspiration.

The fabrics of the present invention allow for regulation of temperature and microclimate that form between the skin surface and the layers of clothing closest to the skin. This microclimate has the greatest importance in terms of wearing comfort.

Furthermore, the textile according to the invention advantageously also the principle of self-cleaning, analogous to the leaf of the lotus plant and many insect species, on. Due to the high pore density in the nonwoven structure can penetrate no water and / or pollution in the textiles. As a result of nanostructuring, both water and soil remain on the surface of the web. The nonwovens according to the invention therefore protect the textiles from contamination. In addition, the textiles of the invention are characterized by highly effective, long-term water density, with simultaneous breathability.

Important realizable by the process according to the invention product properties are, for. B. "easy to clean" properties, protective layers (barrier layers, overlays, etc.), the targeted construction of switchable nanolayers or structures, electrical conductivity, catalytic activity, catalytic self-cleaning, electromagnetic shielding, substance-specific filtration and binding properties, controlled drug delivery and improved flame resistance, elasticity and processability.

In a further embodiment of the invention, the textiles according to the invention are used in car seat coverings, in air filters of air conditioning systems, in the form of awnings and fabric coverings on buildings or as covers of operating tables in hospitals.

According to the process of the present invention, advantageous polymer blends can be prepared which can be spun into a complex material by combining two or more different and structurally compatible nonwoven webs to produce structural or functional properties which the individual components alone do not possess.

In one embodiment of the invention, the nonwovens of the invention are used for catalysts, whereby they can be used for catalytic processes. The nonwovens according to the invention consisting of nanofibers have excellent properties, in particular a large specific surface and a high permeability to liquids and gases. In addition, structuring of the fibers in micro and nano-regions forms a stable nonwoven and allows easy handling.

The immobilization of the catalyst exclusively in the nanofibers is by

Electrospinning a mixture of polymer matrix with catalyst or precursor of a catalyst takes place. In the resulting nanofibers, the catalysts are encapsulated within the nanofibers, with the web acting as a semipermeable membrane. This immobilization allows short diffusion paths and thus a reduced Stofftransportlimitierung. Thus, the catalyst immobilized nanofibers show shorter reaction times than conventional films, but also lower sensitivities because of the lower contact resistance, and concomitantly with increased activity of the immobilized catalyst (a fast response time).

Compared to conventional thin films can also be the

Significantly reduce catalyst concentration through molecular dispersion in association with nanostructuring of the web. In this way, the residual concentration in the final products can be kept low.

For applications in medicine, pharmacy, electronics and optoelectronics, especially the synthesized products must be present in high purity. That is, the catalyst should be easily separable from the product on a larger scale. The immobilization within the nanofibers allows such recovery of the catalyst from the reaction medium to a very high percentage.

The spectrum of useful catalysts for the nonwoven web of the present invention is very broad, starting with metals including gold, silver, osmium, ruthenium, palladium and platinum, via inorganic compounds, e.g. Semiconductors (lead sulfide, cadmium sulfide, titanium dioxide, zinc oxide, and more) and zeolites, to biomolecules or enzymes.

These novel catalysts combine ease of use, general

Usability and high activity. The nonwovens functionalized with various catalysts can be used in chemical synthesis.

For use in nanoelectronic circuits and devices Catalysts and electronically active materials by means of PVD processes or SoI gel coating processes are deposited on the nanofibers of the invention.

Improved sensor properties are achieved by the finer structuring of the nanofibers according to the invention in the nonwovens according to the invention. In addition to a much faster response time based on the short distances between the catalyst and the reaction medium, the nonwovens according to the invention can detect as sensor materials vapors and metal ions sensitive to thin film sensors by two to three orders of magnitude. As a result, the nanofibers according to the invention can be used for the development of gas detectors.

In a further embodiment of the invention, novel highly active biocatalysts for reactions in organic solvents are obtained by the addition of enzymes in electrospinning. Due to their high porosity, the nonwovens according to the invention are intended for use in biosensors and biofuel cells.

In a further embodiment of the invention, the inventive

Nanofibers used as part of optoelectronic components. The electrospun nanofibers consisting of conjugated polymers have been shown to possess outstanding photo and electroluminescence as well as photovoltaic and nonlinear optics properties. For example, nanofibres can be considered as promising materials for optoelectrical components.

Conjugated polymers are an important class of materials because of their semiconductor properties. Formally similar to inorganic semiconductors, very high electrical conductivities can be achieved by doping, which is why they are also referred to as "synthetic metals".

The range of applications of the materials according to the invention ranges from materials for organic light emitting diodes, nonlinear optics and organic polymer lasers over polymers for photovoltaic applications (solar cells) to semiconductor polymers for polymer electronics (field effect transistors), computer chips and the screen technology.

Compared to the conventional semiconductors, especially in the development of cost-effective large-area yet flexible screens, the polymeric electroluminescent materials are a real alternative to the conventional cathode ray tube screens and liquid crystal displays (LCDs). Furthermore, these can lead to the development of very luminous monochrome and color displays, for example for mobile phones or computer screens, which, in contrast to the previously used LCD technology have some significant advantages, such as lower power consumption with higher luminosity and better contrast or independence from the perspective.

Conjugated polymers are particularly versatile, since fine tuning of their properties (color, quantum yield) by changing the structure is easily possible. Nanostructured polymer materials claim an ever growing interest as active or passive components in electronic components.

One-dimensional nanofibers made of conjugated polymers are novel, inexpensive, and flexible building blocks that combine electronic, optical, and mechanical properties that are potentially suitable for use in functional optical and electronic nanoscale devices.

In one embodiment of the invention, a light emitting diode consists of semiconductive polymeric nanofibers. This results in a promising, cheap and tiny little powerful light source.

In a further embodiment of the invention, the nonwovens based on electroluminescent nanofibers according to the invention are used in lasers, flat screens and illuminations.

The color tuning of the webs according to the invention, e.g. Red, yellow and green, can be adjusted by using the appropriate polymeric semiconductors. By incorporating active molecules (chromophores), the emission of electrospun fibers from visible to near-infrared wavelengths (NIR) can be easily tuned.

In a further embodiment of the invention, the near-infrared light-emitting nanofibers are used for applications in communication networks, biosensing and diagnostics based on photonic technologies.

Because of fiber size, emission from the light-emitting electrospun nanofibers on the nanoscale is limited. However, this results in an attractive property for applications in the field of nanoparticles due to the increased charge mobility and the ultrafast charge-discharge ratio in the nanofibers Sensors that require highly localized excitation of the molecules, eg for DNA and protein sensing.

In a further embodiment of the invention, the nanofibers according to the invention are used with higher sensitivity and selectivity because of their extremely high intrinsic specific surface area for sensor systems (chemical resistance).

Acids, bases, oxidizing substances, anions, cations, inorganic and organic gases can influence the electrical conductivity of the nonwovens according to the invention.

In a further embodiment of the invention, the nanofibers of the invention consisting of conjugated polymers are used in field-effect transistors. Technologically, field effect transistors are the important other conjugate polymer based devices as they form the basic building block in the logic circuits and the switches for screens.

The nonwovens of the invention therefore open up the possibility of high throughput and cost-effective production of fully organic photonic systems based on coherent emitters.

In a further embodiment, the nonwovens according to the invention are used in solar cells. In the solar cells are the nonwovens of the invention, which are used as a solution of the semiconducting polymers with the acceptor molecules, e.g. Fullerenes (C60), electrospun, are used. In this way, an inventive, light-absorbing fleece, in which the interface between the polymer and the electron-accepting acceptor phase is distributed over the volume of the layer, wherein the light-generated electrons pass quickly from the polymer to the acceptor molecule and the distance required for the removal of the charges be overcome as quickly as possible to the electrode.

The basic advantages of a solar cell based on the nonwovens according to the invention over conventional ones are low production costs due to low-cost production technologies, high current yields by increasing the specific surface area as well as flexibility and simple handling.

In a further embodiment of the invention, the organic photovoltaic systems produced on the basis of the nonwovens according to the invention are designed to be rollable. In a further embodiment of the invention described above, the organic photovoltaic systems produced on the basis of the nonwovens according to the invention are integrated into chip cards and textiles.

In a further embodiment of the invention, the nonwovens according to the invention, consisting of polymeric semiconductors, are used as electrostatic discharge protection,

Corrosion protection and shielding used against electromagnetic interference.

In a further embodiment of the invention, magnetic nanoparticles are added prior to spinning the polymer solution / melt. Magnetic nanoparticles are of great interest for a wide variety of applications ranging from ultra-high data storage and catalysis to biotechnology / biomedicine due to their many exceptional properties; z. B. for the electrochemical biosensors, Bioseparatoren, the detection of DNA, RNA, cell and proteins, controlled Transportbzw. Medication and gene delivery systems, nuclear magnetic resonance imaging as a contrast agent, hyperthermic treatment for tumor or cancer cells.

Magnetic nanoparticles having a multiplicity of different compositions and phases are used in the process according to the invention; for example with Fe ₃ O ₄ and Y-Fe ₂ O ₃ , pure metals such as Fe, Ni and Co, spinel-like ferromagnets such as MFe ₂ O ₄ (where M is a metal such as Mn, Co, Ni, Cu, Zn, Mg, Cd etc and alloys such as CoPt ₃ and FePt, and magnetic nanocrystals such as Cr ₂ O ₃ , MnO, Co ₃ O ₄ and NiO.

Regardless of the application of the magnetic nanoparticles in the nanofibers, maintaining particle stability over an extended period of time without agglomeration or precipitation presents an increased difficulty.

By means of the electrospinning process according to the invention, such stability can be easily achieved by immobilization or encapsulation of the nanoparticles within the nanofibers. In the nonwovens of the invention, the polymer matrix serves as a protective shell not only to protect the magnetic nanoparticles against oxidation and erosion or decomposition, but also for further functionalization, for. With catalytically active species, drugs, specific binding sites or other functional groups.

In a further embodiment of the invention, the magnetic nanoparticles are used in catalysis and in the separation of biological species. Ferromagnetic nanoparticles whose size is below a critical value, typically about 10 nm in diameter, exhibit superparamagnetic behavior, meaning that they can be magnetized with an external magnetic field and immediately redispersed after removal of the magnet.

These properties make superparamagnetic nanoparticles very interesting for a wide range of biomedical applications, since the risk of agglomerate formation at room temperature is negligible.

Such a magnetic behavior in the form of a simple on / off circuit is a particular advantage of the magnetic separation.

Particularly in the case of catalytic reactions in the liquid phase, such small, multifunctional, magnetically separable particles have great potential, since the nonwovens according to the invention combine the advantages of a large dispersion, high reactivity and easy separability.

The nonwovens of this invention containing such magnetic nanoparticles may be useful as magnetically switchable bioelectrocatalytic systems for the efficient, rapid, easy separation and reliable capture of catalysts, radioactive waste, biochemical products, genes, proteins and cells.

The collection and subsequent separation of low concentration biomolecules, e.g. DNA / mRNA target molecules with the nonwovens according to the invention are of great interest for the diagnosis of diseases

Gene expression studies and the study of gene profiles.

In one embodiment of the invention, the nonwovens according to the invention consist of biocompatible polymers with magnetic nanoparticles to which pharmaceutically active ingredients are bound. These are used as magnetic-drug-targeting drugs.

In a further embodiment of the invention, nanoparticles are used simultaneously as contrast agents in addition to the pharmaceutically active substances. This results in addition to the directed magnetic field-controlled drug application also a real-time control option by means of magnetic resonance imaging.

The nonwovens according to the invention can transport a high dose of the active ingredient and thus bring about a high local active ingredient concentration in situ. Toxicity and other side effects from high systemic drug dosing in other parts of the body Organisms are avoided.

In a further embodiment of the invention, the magnetic nanoparticles are used in the hyperthermic treatment. It is considered to be complementary to chemotherapy, radiotherapy and surgical intervention in cancer therapy. The idea of using magnetic induction hyperthermia is based on the fact that heat is produced due to magnetic hysteresis loss (Neel and Brown relaxation) when magnetic nanoparticles are exposed to an alternating magnetic field.

When a nonwoven according to the invention is exposed to an alternating magnetic field, these introduced superparamagnetic particles become strong heat sources which destroy the tumor cells, since these cells are more susceptible to temperatures than healthy cells.

In a further embodiment of the invention, purely magnetic fibers are produced by spinning polymers with suitable precursors and subsequent thermal treatment of the spun fibers. The magnetic fiber nonwoven webs of the present invention are used for high data density storage media, magnetic logic junctions, spintronic devices, magnetic sensors, and magnetic composites.

In a further embodiment, metallic, ceramic and their hybrid nanofibers are prepared by electrospinning either directly from the respective precursor materials or if they can not be electrospun - a sufficiently viscous polymer solution containing the precursor materials, the polymer acting as a carrier.

The resulting organic-inorganic precursor nanofibers can be structured or aligned according to the invention with the aid of a suitable template. The nonwoven webs of these fibers are then thermally treated (e.g., in an oven at a temperature which results in degradation of the matrix polymer to directly or readily pyrolytically sublime the polymeric constituent). The associated pyrolysis of the matrix polymer effectively removes the polymeric constituents, so that they are purely inorganic, composed of metals,

Ceramics or metal / ceramic hybrid materials existing nanofibers are obtained.

In this way, the nonwovens according to the invention are made of numerous Nanofibres, such as metals; Cu, Fe, Ni, Co Pd and Fe ₃ O ₄ , etc., ceramics; ZnO, TiO ₂ , NiO, CuO, MgO, Al ₂ O ₃ and prepared. Further, the fibers can also Kobaltnitrtat and Kobaltdinitrat, iron nitrate and Ferric nitrate (Fe (NO ₃₎ ₃ ^* 9H ₂ O), nickel (II) - acetate tetrahydrate or palladium acetate, etc. exist. Based on this principle, it is also possible to produce carbon nanofiber nonwovens from electrospun polyacrylonitrile nanofibers.

In a further embodiment of the invention, because of their very large specific surface area with excellent mechanical stability, the nanostructured ceramic nonwovens according to the invention open in hot gas filtration and in the production of electricity from machine exhaust gases.

In a further embodiment, the nanostructured ceramic nonwovens according to the invention are used in all applications in which conventional ceramic materials have hitherto been used. For example, the nanostructured ceramic webs of the present invention are used in catalysis, fuel cells, solar cells, membranes, hydrogen storage batteries, structural applications requiring high mechanical stiffness for biomedical applications such as tissue engineering, biosensors used, etc.

In one embodiment of the invention nanostructured ceramic oxides also find applications in the field of nanoelectronics, sensors, resonators and in opto-and magneto-electronic devices due to their special electronic properties.

Due to the specific surface area of the nonwovens according to the invention, the collecting capacity of the submicrometer particles can be increased, so that a new generation for gas sensors in the climatic and medical applications can be generated.

In a further embodiment of the invention, the polymeric nonwovens according to the invention are used as templates for the production of freestanding large-area nanostructured nonwovens consisting of nanotubes, these nonwovens having at least one inorganic component.

In this case, the nonwoven fabric according to the invention is first coated with a so-called jacket material. Depending on the material used, different ones are available

Techniques to apply the cladding material on the fibers. Exemplary are chemical vapor deposition (CVD), sputtering, spin coating, sol gel method, dip coating, spraying, plasma deposition or Atomic layer deposition (English, atomic layer deposition, ALD) called.

In one embodiment of the invention, the deposits are preferably carried out from the gas phase. This not only achieves a very uniform thick layer around the fibers and very accurate reproducibility of the surface topology of the template fibers, but also impurities, e.g. avoided by solvents.

Particularly suitable is the ALD, in which takes place in contrast to CVD, the layer growth in a cyclic manner. The self-controlling growth mechanism of ALD facilitates the control of film thickness and composition at the atomic level, allowing deposition on large and complex surfaces. After deposition of the inorganic phase on the nanofibers, the polymer matrix is removed by pyrolysis.

In this way, complex structured nonwovens can be easily and quickly replicated with inorganic materials. Depending on the available precursor materials, the freestanding nonwovens consisting of metals, ceramics and the hybrid nanotubes can be produced. Generally, the

Tube geometry considerable advantages, since nanotubes can be used both as lines as well as microcavities or microcapsules.

The nonwovens according to the invention with precisely defined nanoscale walls form nanostructured systems which can be handled easily and have an extremely large surface area, which can be used advantageously in comparison with systems made of conventional nonwovens, for example in catalysis or in sensors.

The properties of the webs consisting of nanotubes of at least one inorganic constituent can be tailored to the respective application by functionalizing the walls of the nanotubes.

The surface morphology of the nanofibers, which is characterized by phase transitions or

Targeted adjustment of phase separation processes manifests itself in a nanosurface or nanoporosity of the tube walls. As a result, the surface of the tube wall is increased again, which is the case for many applications, eg. As in catalysis, separation or sensor technology, is advantageous.

In one embodiment of the invention, the additional nanopores can be described as

Use containers for the transport of molecules, messengers and active substances.

The successive coating with different wall materials expands the spectrum on multi-layer nanotubes and also multi-component systems and composites with a defined composition, which can be formed into nanotubes.

In a further embodiment of the invention, the nanofibers according to the invention can be formed into hybrid nanotubes with a core-shell morphology by additional coating with one or more precursor materials.

The nanotubes according to the invention or the nonwovens consisting of the nanotubes can be used in many ways.

In one embodiment of the invention, the nanotubes or the nonwovens consisting of the nanotubes are used in the medical and pharmaceutical fields (tissue engineering, galenics, antifouling), transport and separation, in sensor technology (gas, moisture and biosensors), substance storage ( Fuel cells), microelectronics (interlayer dielectrics), electronics (nanocircuits, nanocables, nanocapacitors) and in optics (light pipe, nanoglass tubes for optical near-field microscopy).

According to the invention, the polymer solution is released from an application device, for example a spinning capillary, under pressure. For example, the polymer solution can be released by hand from a syringe by means of a spray pump.

In one embodiment of the invention, the release of the polymer solution by means of a spray pump by hydraulic, mechanical or pneumatic means.

In a further development of the above-described embodiment, the release of the polymer solution can be automated. For this purpose, the hydraulic pump, driven by hydraulic, mechanical or pneumatic means pump controlled computationally.

In another embodiment, the syringe is movably arranged and can be moved in the x-y-z direction.

In a further development of the above-described embodiment, the relative movement of the syringe is controlled computationally.

In a further embodiment, the template is arranged to be movable and can be moved in the xyz direction.

In a development of the above-described embodiment, the relative movement of the template computationally controlled.

In another embodiment, both the syringe and the template are movably arranged and can be moved in the x-y-z direction.

In a further development of the above-described embodiment, the relative movement of the syringe and the template are computer-controlled.

By means of the computational control of the relative movement of the syringe and / or of the template, the deposition of the nanofibers can be reproducible, which is necessary in particular in the field of mass production with high quality requirements.

The invention will be explained in more detail with reference to some embodiments. The accompanying drawings show in

A schematic representation of the electrospinning process of conventional type, in

A representation of the nanofibers produced in the conventional manner, in

A representation of a template used in the conventional manner and the nanofibers produced therewith, in

4 shows an illustration of a further template used according to the conventional manner and of the nanofibers produced therewith, in FIG

Fig. 5 is a schematic representation of the electrospinning process according to the invention with template, in

Fig. 6 is a schematic representation of a template according to the invention, in

FIG. 7 shows a representation of exemplary template structures according to the invention and the resulting nanofiber structures according to the invention, and FIG

8 shows a representation of the nanofibers produced according to the invention.

The device for electrospinning suitable for carrying out the method according to the invention, shown in FIG. 5, comprises a syringe 1 in which a polymer solution or melt 2 is located. At the tip of the syringe 1 is a spinning capillary 3, which is coupled to one pole of the voltage generating arrangement (power supply) 6. The polymer solution or melt is by means of a spray pump 9 the Polymer solution or melt 2 transported from the syringe 1 in the direction of spinning capillary 3, where it comes as a result to a droplet formation at the top of the spinning capillary 3. By an electric field between the spinning capillary 3 and a counter electrode 5, the surface tension of the emerging from the spinning capillary 3 drop of the polymer solution or melt 2 is overcome and as a result, the emerging from the spinning capillary 3 drops is deformed and upon reaching a critical electrical potential to a thin thread, the so-called jet, pulled out. This electrically charged jet, which now continuously draws out new polymer solution or melt 2 from the spinning capillary 3, is then accelerated in the electric field in the direction of the counter electrode 5. He is subjected to a very complex manner of bending instability (the so-called Whipping Mode), vigorously rotated and stretched. The jet solidifies during its flight to the counter electrode 5 by evaporation of the solvent or by cooling, so that nanofibers 7 with typical diameters of a few nanometers to a few micrometers are produced within a few seconds. These nanofibers 7 are deposited on the template 8 (FIGS. 7B, D) connected to the counterelectrode 5 in the form of a nonwoven mat, the nonwoven mat (FIGS. 7A, C). The conductive template 8, which is located on a conventional conductive counter-electrode 5, serves as a collector 4 and is grounded together with the counter-electrode 5. The polymeric nanofibers 7 are spun directly onto the template 8. The nanofibers 7 are preferably deposited in the region of the structured template 8 within the counter electrode 5, since the electric field strength has maximum values there. In addition, the helical airline of the jet as it approaches the template 8 is severely restricted by Coulomb's interaction between it and the oppositely charged or grounded template 8 only on the lattice towers within the template 8. In the intermediate areas of the lattice towers within the template 8, in which there is no conductive material (as in the holes of a screen), hardly or no nanofibers 7 are deposited. Thus, the control of the deposition position with the simultaneous patterning of jets is possible. Is the template 8 on the entire width at least simple of the

Nanofiber 7 covered, the spinning process can be interrupted. Subsequently, the deposition layer of electrospun fiber 7 for obtaining the freestanding nonwoven whose structure corresponds to that of the template 8 (Figs. 7A, C) is carefully separated from the template 8 (Fig. 7B, D). The resultant fleece is available for use or possible after-treatment. After removal of the web, the template 8 can be used immediately for further electrospinning operations. The nanofibers 7 are devoured by repeated attachment and stacking in the form of a three-dimensional nonwoven mat (FIG. 8). The size and shape of the voids between the fibers 7 in such webs can be easily controlled by the choice of the template 8.

In one embodiment of the invention, the template 8 is used directly as a collector 4. As a result, deposition of the nanofibers 7 can only take place in the region of the lattice masts on the template 8.

In an embodiment of the invention, in FIG. 6, the lattice masts of the template 8, which are designed, for example, as wires, wire screens or perforated metal lattices, have a ratio of the width (b) of the lattice masts to their thickness (d) of> 1. This means that the lattice masts are wider than thick. The width (b) of the lattice masts in this case characterizes the expansion in the x and / or y direction, while the thickness (d) of the lattice masts in this case refers to the material thickness of the lattice towers of the template 8 in the z direction. One is particularly advantageous if the material of the template 8 in the z-direction is substantially smaller than in the x and / or y direction.

In one embodiment of the invention, pharmaceutical active substances are mixed in as nanoparticles before spinning into the polymer solutions or melts 2 with different dimensionalities and then applied to the template 8 together with the polymer.

In a further embodiment, the surface of the above-described nanofibers 7 is modified by means of atomic layer deposition. As a result, nanofibers 7 can be tailored according to their application by modifying the surface of the nanofibers 7.

In a further embodiment of the invention, the above-described modified nanofibers 7 are subjected to a thermal treatment at 500 ^° C. in an oven. As a result, the polymeric portion of the nanofiber 7 is removed, leaving only the inorganic portion of the nanofiber 7 remains.

In a further embodiment of the invention, ceramic nanofibers 7 are produced by the above-described electrospinning process according to the invention. For this purpose, the polymer solution or melt 2 ceramic precursors from the group consisting of Al ₂ O ₃ , CuO, NiO, TiO ₂ , SiO ₂ , V ₂ O ₅ , ZnO, Co ₃ O ₄ Nb ₂ O ₅ , MoO ₃ and MgTiO ₃ mixed and then electro-spun. As a result, ceramic nanofibers 7 can be produced which can be used, for example, in composite materials. Template-based patterning procedure of nanofibers in electrospinning

Methods and their applications

LIST OF REFERENCES

1 syringe

2 polymer solution or melt

3 spinning capillary 4 collector

5 counter electrode

6 power supply

7 deposited nanofibers

8 Template 9 Spray Pump

b Width of the lattice mast of the template d Thickness of the lattice mast of the template

Claims

Template-assisted Pattern Forming of Nanofibers in the Electrospinning Process and Applications 5 Patent claims

A method of making two- and three-dimensionally structured nanofiber micro- and nanoporous nonwoven webs by electrospinning, characterized in that for forming the webs in any shape having a degree of coverage of the nanofibers (7) of more as 60% of a predefined conductive template (8) is used as a collector (4), wherein the structure of the nonwovens to be generated by the template (8) is specified.

2. The method according to claim 1, characterized in that zur5 extraction of the freestanding nonwoven whose structure corresponds to that of the template (8), is separated from the template (8), wherein after removal of the nonwoven template (8) immediately for further electrospinning Operations can be used.

3. Process according to claims 1 and 2, characterized in that an o polymer solution or melt (2) is used for producing the structured nonwoven fabrics of nanofibers (7), wherein suitable as

Polymers all known natural and synthetic polymers, mixtures of polymers with each other (polymer blends) and copolymers, consisting of at least two different monomers, as far as they are meltable and / or at least soluble in a solvent used. 5

4. The method according to claim 3, characterized in that the

Preparation of structured nonwovens Polymers from the group consisting of polyesters, polyamides, polyimides, polyethers, polyolefins, polycarbonates, polyurethanes, natural polymers, polylactides, polyglycosides, poly (alkyl) methylstyrene, polymethacrylates, polyacrylonitriles, latices, polyalkylene oxides aus0 ethylene oxide and / or propylene oxide and mixtures thereof.

5. Process according to claims 3 and 4, characterized in that the polymers or copolymers selected from the group consisting of poly (p-xylylene); Polyvinylidene halides, polyesters such as polyethylene terephthalates, polybutylene terephthalate; polyether; Polyolefins such as polyethylene, polypropylene, Poly (ethylene / propylene) (EPDM); polycarbonates; polyurethanes; natural polymers, eg rubber; polycarboxylic acids; polysulfonic; sulfated polysaccharides; polylactides; polyglycosides; polyamides; Homopolymers and copolymers of vinyl aromatic compounds such as poly (alkyl) styrenes), for example polystyrenes, poly-alpha-methylstyrenes; Polyacrylonitriles, polymethacrylonitriles;

polyacrylamides; polyimides; Polyphenylene; polysilanes; polysiloxanes; polybenzimidazoles; polybenzothiazoles; polyoxazoles; polysulfides; polyester; Polyarylene-vinylenes; polyether ketones; Polyurethanes, polysulfones, inorganic-organic hybrid polymers; silicones; wholly aromatic copolyesters; Poly (alkyl) acrylates; Poly (alkyl) methacrylates; polyhydroxyethylmethacrylates; Polyvinyl acetates, polyvinyl butyrates; polyisoprene; synthetic rubbers such as chlorobutadiene rubbers; Nitrile-butadiene rubbers; polybutadiene; polytetrafluoroethylene; modified and unmodified celluloses, homopolymers and copolymers of alpha-olefins and copolymers made up of two or more monomer units forming the abovementioned polymers;

Polyvinyl alcohols, polyalkylene oxides, e.g. Polyethylene oxides; Poly-N-vinylpyrrolidone; hydroxymethylcelluloses; maleic; alginates; Polysaccharides such as chitosans, etc .; Proteins such as collagens, gelatin their homo- or copolymers and mixtures thereof.

6. The method according to claims 3 to 5, characterized in that for the preparation of the nanofibers (7) a polymer solution or melt (2) of the polymers according to claims 3 and 4 is used, said solution or melt (2) from a Solvents or mixtures of solvents with the polymers.

7. The method according to claim 6, characterized in that the solvents used from the group consisting of chlorinated solvents, such as dichloromethane or chloroform; Acetone; Ethers, for example diethyl ether, methyl tert-butyl ether; Hydrocarbons having less than 10 carbon atoms, for example n-pentane, n-hexane, cyclohexane, heptane, octane, dimethyl sulfoxide (DMSO), N-methylpyrrolidinone (NMP),

Dimethylformamide (DMF), formic acid, water, liquid sulfur dioxide, liquid ammonia, and mixtures thereof.

8. The method according to claims 6 and 7, characterized in that the mixing of the spinnable polymer solutions or melts (2) with stirring, under the action of ultrasound or under the action of heat is carried out.

9. The method according to claims 3 to 8, characterized in that the concentration of the at least one polymer in the solution or melt (2) at least 0.1 wt .-%, preferably 1 to 30 wt .-%, particularly preferably 2 to 20 wt .-% is.

10. The method according to claims 3 to 9, characterized in that prior to spinning into the polymer solutions or melts (2) nanoparticles are mixed with different dimensionalities and then applied together with the polymer as nanocomposite nanofibers on the template (8) ,

11. The method according to claim 10, characterized in that metals and / or semiconductors, color pigments, catalysts, pharmaceutical agents, enzymes, antiviral or antibacterial agents, biological messengers (such as DNA, RNA and proteins) as nanoparticles before spinning into the polymer solutions or -melting (2) are mixed and then applied together with the polymer on the template (8).

12. The method according to claim 10, characterized in that ceramic nanofibers (7) from a mixture of the polymer solution or - melt (2) with ceramic precursors, which consists of the group

Al ₂ O ₃ , CuO, NiO, TiO ₂ , SiO ₂ , V ₂ O ₅ , ZnO, Co ₃ O ₄ Nb ₂ O ₅ , MoO ₃ and MgTiO _{3 are} selected prior to spinning into the polymer solutions or melts (2) be mixed with different dimensionalities and then applied together with the polymer on the template (8).

13. The method according to claims 1 to 12, characterized in that the nonwovens are modified by means of chemical and / or physical processes.

14. The method according to claim 13, characterized in that a surface modification of the nonwovens by coating or irradiation with high-energy radiation, with low-temperature plasma or chemical reagents, eg aqueous hydroxide solution, inorganic acids, acyl anhydrides, or other depending on the Surface functionality with silanes, isocyanates, organic acyl halides or anhydrides, alcohols, aldehydes or alkylating chemicals with their corresponding Katalyten occurs.

15. The method according to claims 13 and 14, characterized in that a modification of the nanofibers (7) in the

Nonwovens are formed by cladding the nanofibers (7) by vapor deposition, sputtering, spin coating, dip coating, spraying, plasma deposition, sol-gel or atomic layer deposition.

16. The method according to any one of claims 1 to 10, d a d u r c h characterized in that for the preparation of the structured nonwovens

Nanofasern (7) is a polymer solution or melt (2) is used, wherein the polymer solution or melt (2) is added to inorganic materials, then electrospun and finally removes the polymeric portion of the electrospun nanofiber (7) which causes the remaining inorganic fractions as inorganic nanofibers

(7) remain.

17. The method according to claim 16, characterized in that

a two-dimensionally and three-dimensionally structured nanofiber (7), microporous and nanoporous nonwoven fabric according to a method according to claims 1 to 15 is produced,

- A modification of the nanofibers (7) in the nonwovens by wrapping the

Nanofibers (7) by gas phase deposition, sputtering, spin coating, dip coating, spraying, plasma deposition, sol-gel method or atomic layer deposition with an inorganic material takes place and

- The polymer is removed by sheathing the nanofibers (7) by thermal, chemical, radiation-induced, biological, photochemical methods, and methods by means of plasma, ultrasound, hydrolysis or by extraction with a solvent.

18. The method according to claims 16 and 17, characterized in that the removal of the polymer material at 10-900

° C and 0.001 mbar to 1 bar and completely or in a proportion of at least 70%, preferably at least 80%, particularly preferably at least 99%.

19. Nanofiber (7) or two- and three-dimensionally structured, consisting of nanofibers (7) consisting of micro- and nanoporous nonwoven, I d n e rch ke n nze I n et that this fleece produced by a process according to claims 1 to 18 is.

20 nanofiber (7) or two- and three-dimensionally structured, consisting of nanofibers, microporous and nanoporous nonwoven fabric according to claim 19, d ad u rc h characterized in that the nanofiber (7) consists of electrospun and oriented fiber bundles.

21. nanofiber (7) or two- and three-dimensionally structured, consisting of nanofibres (7), microporous and nanoporous nonwoven fabric according to claim 20, characterized in that the nanofibers (7) are interconnected by adhesion forces, whereby the resulting nonwovens together with the orientation of the fibers (7) in the nonwovens and the orientation of the microcrystallites, macromolecules, nanoparticles etc. within the fibers (7) have self-reinforcing properties.

22 nanofiber (7) or two- and three-dimensionally structured, consisting of nanofibres (7), microporous and nanoporous nonwoven fabric according to claim 21, characterized in that the nanofibers (7) a coverage or degree of deposition of the nanofibers in the range between 60 and 100%.

23. Nanofiber (7) or two- and three-dimensionally structured, consisting of nanofibres (7), microporous and nanoporous nonwoven according to claims 19 to 22, characterized in that the nanofibers (7) are composed of at least one polymer selected from Group consisting of polyesters, polyamides, polyimides, polyethers, polyolefins, polycarbonates,

Polyurethanes, natural polymers, polysaccharides, polylactides, polyglycosides, poly (alkyl) methylstyrene, polymethacrylates, polyacrylonitriles, latices, polyalkylene oxides of ethylene oxide and / or propylene oxide, and mixtures thereof.

24. nanofiber (7) or two- and three-dimensionally structured, consisting of nanofibres (7), microporous and nanoporous nonwoven according to claims 19 to 23, characterized in that the nanofibers (7) enveloped by means of vapor deposition, sputtering, spin coating , Dip-coating, spraying, plasma deposition, sol-gel process or atomic layer deposition enveloped are.

25. nanofiber (7) or two- and three-dimensionally structured, consisting of nanofibres (7), microporous and nanoporous nonwoven according to claims 19 to 24, characterized in that the nanofibers are prepared according to a method of claims 16 to 18 and at least have an inorganic component.

26. Nanofiber or two- and three-dimensionally structured, nanofibers, microporous and nanoporous nonwoven fabric according to claims 19 to 25, in which the nanofibers (7) are functionalized with nanoparticles in the form of pigments, dyes,

Chromophores, catalysts, messengers, inorganic materials, metals, conductive materials, ceramic precursors, magnetic particles, semiconductive materials, pharmaceutically active agents, fragrances, messengers, proteins, enzymes, DNA, RNA, mRNA, antibiotic agents, biocompatible materials or mixtures thereof exhibit.

27. Use of the nanofiber or the two- and three-dimensionally structured nanofibers (7) consisting of microporous and nanoporous nonwoven fabric according to one of claims 19 to 26 for use in the following applications: filter or filter parts; electrical and opto-electrical applications; in microelectronics,

Electronics, photovoltaics, optics; Photovoltaic applications; Semiconductor polymers for polymer electronics, in field effect transistors, computer chips, on-screen technology, electromagnetic interference shielding, in communication networks, for use with high-density storage media, magnetic logic junctions, spintronic devices; magnetic sensors and magnetic composites; in the sensor system; as a component or coating of textiles for technical, medical or household textiles; Component of composite materials; as part of ultralight nanocomposites; in biotechnological applications; Corrosion protection; as a semiconductor; in the medical and pharmaceutical

Area, transport and release of active substances, as support tubes for the regeneration of blood vessels, esophagus and nerves, support tubes with pharmaceutically active substances, for the surface modification of implants; Transport and separation, for use in wound healing or as a wound dressing, as a cause-specific wound plaster with special active ingredients for the treatment of chronic diseases, as porous membranes and temporary skin replacement, in medical diagnostic applications, in the directed magnetic field-controlled drug application, in hyperthermic treatment, as magnetically switchable bioelectrocatalytic systems; as a carrier for catalysts for catalytic processes; Sequestration;

Fuel cells, ceramic materials.

28. An apparatus for carrying out a method according to claims 1 to 18 with an electrospinning device with a spinning capillary (3) and a collector (4), which is designed as a counter electrode (5) to the spinning capillary (3), and an electrical voltage between A spinning capillary (3) and collector (4) generating voltage generating arrangement (6), characterized in that as a collector (4) a predefined structured conductive template (8) which corresponds to the structure of the nanofibers (7) to be generated, on the conductive counter electrode (5) is detachably arranged or forms the counter electrode (5).

29. Apparatus for carrying out a method according to claim 28, characterized in that the template (8) consists of a conductive material, which may be e.g. in the form of wires and wire sieves or perforated metal meshes, etc., of metallic materials or semiconductors or in the form of natural or man-made fibers which increase their surface area

Conductor were impregnated with a conductive agent is present.

30. A device for carrying out a method according to claims 28 and 29, characterized in that the template (8) is produced by means of conventional microfabrication techniques.