Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B81—MICROSTRUCTURAL TECHNOLOGY
  • B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
  • B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
  • B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
  • B81C1/00206—Processes for functionalising a surface, e.g. provide the surface with specific mechanical, chemical or biological properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C59/00—Surface shaping of articles, e.g. embossing; Apparatus therefor
  • B29C59/02—Surface shaping of articles, e.g. embossing; Apparatus therefor by mechanical means, e.g. pressing
  • B29C59/022—Surface shaping of articles, e.g. embossing; Apparatus therefor by mechanical means, e.g. pressing characterised by the disposition or the configuration, e.g. dimensions, of the embossments or the shaping tools therefor
  • B29C59/025—Fibrous surfaces with piles or similar fibres substantially perpendicular to the surface
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
  • Y10T428/24479—Structurally defined web or sheet [e.g., overall dimension, etc.] including variation in thickness

Definitions

• the invention relates to a method for producing a structured surface having a plurality of thread-like projections, and a component produced by this method.
• the photolithography and the etching process only a limited variability in the adjustment of a certain orientation or shape of the surface structures, as z. B. is of interest for the said adhesion effect. Furthermore, with the conventional techniques only limited projections with substructures, such. B. Dickengradienten, o- the predetermined material compositions are prepared.
• DE 103 53 697 describes a casting method for producing a structured surface with columnar elevations of polymer materials. Although this method achieves an increase in the aspect ratio. However, a disadvantage is the high technical complexity of the method and the restriction to surveys with a straight shape.
• the object of the invention is to provide an improved method for producing a structured surface, with which the disadvantages of the conventional techniques are overcome.
• the inventive method should be feasible at low cost, even with extensive surfaces and have a wider scope. It should in particular a high variability in the adjustment of geometric, electrical, optical and / or mechanical properties of the surface structure and in particular allow structures with an increased aspect ratio.
• the object of the invention is also to provide an improved component with a structured surface, which can be produced with reduced technical complexity and reduced costs and enables high variability in the adjustment of physical or chemical properties of the surface.
• the invention is based on the general technical teaching to provide a surface with thread-like projections by pulling a flowable substance between a stamp surface and a pattern surface and the thread connections formed thereby are interrupted.
• the pattern surface carries a predetermined geometric pattern of surface modifications of chemical or topographical type.
• the pattern forms the template of the thread-like projections to be produced.
• the stamp surface has a geometrically unstructured surface.
• the pattern surface and the stamp surface have mutually matching shapes in such a way that, when approaching each other, both surfaces touch each other at least in partial regions which may have a planar or linear extension.
• the flowable substance which is provided in or on one or both of the stamp and pattern surfaces, wets. is the other surface.
• the thread connections are clamped as self-supporting liquid bridges.
• the surface shape of the thread compounds is determined in particular by the viscosity of the substance and the surface tension of the substance in the clamped state.
• the stamping surface is formed by a free surface (fluid surface) of the flowable substance, from which the thread connections are drawn with the pattern surface, during or after the drawing, a hardening of the flowable substance is provided. After a separation of the pattern surface and the fluid surface with an interruption of the thread connections, the desired thread-like projections remain on the fluid surface, the pattern surface or both surfaces.
• the stamp surface is formed by a surface of a solid (solid surface), while the pattern surface carries the flowable substance.
• the flowable substance is arranged on the pattern surface at the separate subareas (islands) with a specific geometric distribution, which is the template for the arrangement of the thread-like
• the second embodiment of the invention has the particular advantage that it can be dispensed with the provision of a reservoir of the flowable substance.
• all of the thread-like projections can be produced simultaneously during the withdrawal of the pattern surface and the interruption of the thread connections. This procedure is considerably simpler than the conventional ones
• the thread-like projections can be produced with an extremely high length-diameter aspect ratio. If the viscosity is sufficiently high, the thread connections between the fluid surface and the pattern surface may have a length that is, for example, 500 times higher than the diameter of the thread connection.
• the above-mentioned object is accordingly achieved by the general technical teaching to provide a component which has a base surface with a multiplicity of thread-like protrusions made of a flowable, hardenable substance, the thread-like protrusions being one in the flowable state due to the surface tension of the substance have formed contour (surface shape).
• the contour of the thread-like projections corresponds at least in sections or locally to a shape which occupies the substance in the flowable state, which is defined between two surfaces.
• the invention provides a method for producing a mass arrangement of thread-like projections on a surface.
• the structure generally has a column, thread, needle, rod or hair shape.
• the thread-like projections form structures with a length in the range of a few tens of nanometers (eg 100 nm) to a few centimeters (eg 3 cm) and a diameter of a few nanometers (eg 10 nm) to a few millimeters (eg 5 mm).
• flowable substance here refers to all liquid materials that can be stretched and stretched between two bodies in a thread-like manner and maintain their shape when stretched. The flowability is given in particular at the operating temperature at which the method according to the invention is carried out.
• a “textured surface” is a surface area of an article that carries a plurality of filamentary protrusions.
• the pattern surface for drawing the thread connections, apart from the congruence with the fluid surface.
• the arrangement of the thread-like projections may be random or self-organized.
• preferred embodiments of the invention are those in which the arrangement of the thread connections and the thread-like projections is represented by a pattern of adhesion islands (first embodiment of the invention) and / or islands of the flowable substance (second embodiment of FIGS Invention) provided on the pattern surface.
• adhesion island here refers to any locally delimited area on the pattern surface whose wettability for the flowable substance is increased in comparison to the rest of the pattern surface or where there is preferential wetting by the flowable substance.
• adhesion contacts are formed upon contact of the fluid surface and the pattern surface between the substance and the adhesive islands. The flowable substance adheres to the adhesive islands, while the pattern area between the adhesive islands has a reduced adhesion.
• the thread connections are localized in the separation of the fluid surface and the pattern surface of the Adphasesin-, so that the geometric distribution of the thread connections and after the breakthrough and the geometric distribution of the thread-like projections through the pattern of adhesion islands on the pattern surface is specified.
• a particular advantage of the invention is that the arrangement of the thread-like projections can be precisely determined by the use of a pattern surface with a specific pattern of the adhesive islands or islands of the flowable substance.
• the thread-like projections z. B. with a regular, z. B. square grid pattern can be arranged.
• the density of the adhesive islands or islands of the flowable substance, and thus the density of the fan-shaped protrusions may vary along the pattern surface so that the structured surface may be fabricated with a surface density gradient of the thread-like protrusions.
• the provision of the adhesive islands or the islands of the flowable substance means a pre-structuring with which the arrangement of the thread-like projections on the base surface is controlled. The pre-structuring is advantageously simple and inexpensive over a large area feasible.
• the topographical structure preferably comprises local elevations of the pattern surface, which first touch the flowable substance upon mutual approach of the fluid surface and the pattern surface. In this case, there are advantages in terms of the exclusive wetting of the adhesive islands.
• the surveys are preferably by a local stage formation, such. B. formed by particles or layers on the pattern surface.
• the topographical structure may be formed by a thread-like projection or a part thereof, which according to the invention has been produced in a preparation process on the pattern surface.
• the topographical structure alternatively comprises local depressions of the pattern surface, e.g. B. in the form of cavities which receive the flowable substance upon contact of the fluid surface and the pattern surface.
• the adhesion islands comprise chemically modified regions of the pattern surface, there may be advantages for improving the adhesion contact between the substance and the pattern surface.
• the chemically modified regions may be specially adapted to the substance from which the filiform protrusions are made in order to achieve good local adhesion.
• Substances for providing chemically modified adhesion islands are preferably the materials of the protrusions or materials to be drawn, which due to their polarity or apolarity form a bond with the material of the protrusions to be drawn.
• the adhesive islands comprise the flowable substance.
• Examples of the second alternative are Y- (COOH) x , Y- (NH) x -NH 2 , Y- (CH 2 J x , methyl methacrylate, Y-) OH, and metals, such as. Gold and silver (Y: a functional chemical building block that combines with the material of the pattern surface, eg, thiols with an OH group to attach to Au or silane groups to reactively form an ester compound with a glass surface).
• the adhesion islands can be formed by a topographical structure which has a chemical modification at the elevations or gradations.
• a chemically modified, topographic structure has the particular advantage of increased flexibility in the choice of the materials involved, in particular on the one hand of the material of the sample surface and on the other hand, the flowable substance.
• the adhesion islands form the bases of the thread connections on the side of the pattern surface.
• the thread connections and the thread-like projections can thereby be impressed with a specific cross-sectional shape.
• circular adhesion islands may be used to create filiform protrusions having a circular cross-sectional area.
• the Young's modulus of the thread-like projections may alternatively be e.g. elliptical or angular adhesive islands are used.
• the second embodiment of the invention advantageously provides a structured component in which the thread-like projections are directly connected to the pattern or stamp surface without additional topographic and / or chemical modification.
• the following different variants can be realized.
• the islands of the flowable substance are firmly connected to the pattern surface.
• the flowable substance and the material of the pattern surface are chemically compatible with one another, ie miscible and / or suitable in particular in the molten state, chemical compounds, eg. B. enter through addition reactions.
• Between the flowable substance and the pattern surface is preferably a chemical compound, for. B.
• the flowable substance and the material of the sample surface have the same chemical composition.
• the thread-like projections on the solid surface are formed by a chemical bond between the flowable substance and the solid surface is generated upon contact of the solid and pattern surfaces. In this case, the islands of the flowable substance with the pattern surface only have to form an adherent compound. A chemical compound is not required.
• the chemical composition of the flowable substance and the material of the solid surface is correspondingly preferably identical.
• the islands of the flowable substance are preferably formed by colloidal polymer particles.
• the polymer particles are preferably made of meltable polymers, such as. As polystyrene or polyacrylates.
• particles with a diameter in the range of 50 nm to 20 ⁇ m, in particular 100 nm to 10 ⁇ m, are preferably used.
• a hardening of the flowable substance in the preparation of the thread-like projections is provided.
• the term "curing" here is a solidification of the substance called, until it is dimensionally stable.
• Curing takes place according to a first variant during the tightening of the thread connections.
• the pulling of the thread connection is automatically terminated by a tearing of the thread connection, as soon as the substance has hardened sufficiently.
• the hardening of the substance is provided only after the interruption of the thread connections. In this case, there may be advantages in reproducibility in adjusting the length of the thread-like projections.
• different curing processes can be used individually or in combination.
• the curing takes place advantageously without additional measures.
• solidification of the substance by cooling or crosslinking of the substance can be provided.
• the crosslinking comprises a change of the internal structure of the thread connection by a chemical or physical action, such.
• the pattern surface which is provided with the adhesion islands and / or the islands of the flowable substance, forms a base element, from which the thread-like projections protrude.
• a stable component is thus created, which can be used directly for further application.
• the thread-like projections are provided on the fluid surface of the flowable substance.
• the hardening of the substance involves not only a stabilization of the thread-like protrusions, but also a conversion of the fluid surface into a solid layer, which in this embodiment forms the base element for the thread-like protrusions.
• the base member and the thread-like projections of the same material are provided.
• a shaping of the thread-like projections in response to an external, physical or chemical action.
• polymers having a temperature or pH-dependent surface tension or specific dielectric or magnetic properties can be used as the flowable substance.
• the thread-like projections z. B. be deformed by a temperature or the provision of a specific pH in the environment or electrical and / or magnetic fields, in particular during curing.
• Another advantage of the invention is the high flexibility in selecting a shape of the thread-like projections. Depending on the desired application of the surface structured according to the invention, for example, straight or curved thread-like projections can be formed.
• the thread connections are stretched in a correspondingly straight manner.
• they may be perpendicular or inclined relative to the adjacent surfaces, eg, the fluid surface or the pattern surface.
• the straight filamentary protrusions may be cured during drawing or after.
• the separation movement of the fluid surface and the pattern surface takes place along a straight, oblique-angled or a curved reference line, so that curved, angled or even twisted projections are produced. In this case, the curing takes place during the pulling of the thread connections.
• a variation of the speed of winding of the thread connections is provided, advantageously an additional thickness gradient along the length of the thread-like projections can be produced. If the speed of the separation movement of the fluid surface and the pattern surface is initially small, then the thread connections initially have a greater thickness than at a later time with a higher speed of the separation movement.
• the flowable substance according to a preferred variant of the invention comprises at least one polymer compound, such as. B. at least one organic polymer or at least one organic / inorganic composite polymer.
• the use of at least one polymer compound has the advantage of a particularly simple control of the curing by solvent removal or tempering.
• Preferably used polymers are polydimethylsiloxane (PDMS) (curable with additional component), polyvinylpyridine, polystyrene, polyphosphazenes and polyethylene glycol.
• the flowable substance contains at least one type of crosslinkable monomer (with unsaturated carbon bonds), such as. As acrylates, Metac- rylates, alkenes, nitriles and other monomer mixtures of two components for a polyaddition, polycondensation o. The like ..
• the flowable substance contains at least one additional substance, with which at least one of the chemical, dielectric, optical and magnetic properties of the thread-like projections are modifiable, there are particular advantages for the adjustment of a certain shape of the projections during the production of structured surface or in the application of the structured surface.
• the thread-like projections contain z.
• magnetic colloids or colloids with special dielectric properties As polyvinylpyridine can be used as an additive, which swells in aqueous-acidic solution, while it contracts in a neutral medium.
• a tip treatment of the thread-like projections can be provided.
• the tip treatment involves generation of thickenings at the free ends of the thread-like projections.
• the tip treatment is provided after the interruption of the thread connections.
• the tip treatment comprises, for example, local heating of the free ends of the thread-like projections. cracks, so that form on these spherical thickenings.
• a coating of the thread-like projections, for. B. by a Vakuumaubamp- tion provided.
• the thread-like protrusions can be embedded in a cover layer. In this case, can be dispensed with a suitable choice of substance on a curing of the thread-like projections.
• Preferred applications according to the invention structured surfaces exist in the formation of adhesive surface and in the gas storage.
• the gas storage is made possible by the dynamic-mechanical properties of the thread-like projections. By a deformation of the projections, the pressure of an external fluid can be compensated and thus a
• FIG. 1 shows a schematic illustration of the first embodiment of the method according to the invention for producing a structured surface
• FIG. 2 shows a schematic illustration of the second embodiment of the method according to the invention for producing a structured surface
• FIG. 8 shows a schematic illustration of an apparatus for producing a structured surface according to the invention
• Figure 9 is a schematic illustration of the formation of a thread-like projection with a curvature
• Figure 10 is a schematic illustration of a switchable surface structure according to the invention.
• FIG. 11 shows different variants of adhesion islands used according to the invention.
• FIGS. 12 to 14 are photographic representations of surface structures produced according to the invention.
• FIG. 15 shows a schematic illustration of a further apparatus for producing a structured surface according to the invention.
• FIGS. 1 and 2 show schematic, enlarged illustrations that are not to scale. It is shown in particular in Figures 1 and 2, the production of a series of only three projections, while in practice linear or surface-shaped arrangements of thread-like projections are produced with a significantly higher number. Furthermore, the projections may in practice have a different shape, in particular at the base of the projections over a small length is given a taper, while over the remaining length of the diameter of the projections is substantially constant.
• FIG. 1A shows a preparatory step in which a flowable substance 20 and a drawing device 30 are provided with a pattern surface 31. 1 and aligned relative to one another.
• the substance 20 is located with a free fluid surface 21.1 z. B. in a vessel.
• the drawing device 30 (FIG. 1A) comprises a drive device and a temperature control device (not shown, see FIG. 6), with which the pattern surface 31.1 can be moved and tempered.
• the pattern surface 31.1 points to the fluid surface 21.1. Both surfaces are flat and aligned parallel to each other, the pattern surface 31.1 carries adhesion islands 32, which serve as a template for the formation of the thread-like projections 11.
• the sample surface 31.1 comprises, for example, a plate-shaped substrate made of an organic substance or an inorganic substance (eg plastics, in particular PDMS, polystyrene, epoxy, PMMA, acrylate, ceramic, metal, semiconductors, in particular Au, Ag, TiO 2 , ZnO 2 , Si, SiO 2 , carbon-based or reinforced composite materials).
• the adhesion islands 31.1 comprise, for example, particles with a diameter of 4 nm, for example gold (so-called gold nanodots), down to the ⁇ m range (eg 100 ⁇ m), eg. B. from colloids of polystyrene, SiO 2 , TiO 2 .
• the adhesion islands 31.1 may be formed by a process of self-assembly on the surface, e.g. Example of polymers from photolithographically produced and / or applied with stamping substances.
• the flowable substance may initially still be solid.
• the preparation step comprises heating the substance 20 with a heating device (not shown, see FIG. 6) to a temperature above the melting or softening temperature of the substance 20.
• PVP polyvinylpyridine
• the PVP solution is applied as a thin layer to a glass surface and dried. Subsequently, the dried PVP layer is heated to soften the polymer.
• PVP is set to approx. Heated to 60 to 140 ° C.
• the pattern surface 31.1 is approximated to the fluid surface 21.1 according to FIG. 1B until the adhesion islands 32 of at least part of the pattern surface 31.1 touch the substance 20.
• a group of adhesion islands 32 touch the fluid surface 21.1 simultaneously. This group can, for. For example, all adhesion islands 32 of the pattern area 31.1 or when using a curved pattern area 31.1, for example on a roller (see FIG. 14), comprise one or more rows of adhesion islands 32.
• the pattern surface 31. 1 can touch the fluid surface 21. 1 so that only the adhesion islands 32 are wetted by the substance 20 become.
• the pattern surface 31.1 can also completely contact or even immerse the fluid surface 21.1, since the substance 20 adheres better to the adhesion islands 32 than in the areas lying therebetween.
• a separation movement of the fluid surface 21.1 and the pattern surface 31.1 relative to one another takes place.
• the pattern surface 31.1 is withdrawn, alternatively or additionally, the fluid surface 21.1 can also be moved (see arrows).
• the movement takes place, for example, vertically or as a shearing movement (see dashed arrow and FIG. 14) relative to the plane of the fluid surface 21.1.
• the speed is chosen depending on the material properties and the desired projection shape and is at the o. G. PVP layer z. In the range of 0.1
• Adhesion with the flowable substance 20 is retained on the surfaces of the adhesion islands 32, so that thread connections 22 are clamped between the adhesion islands 32 and the flat surface 21.1.
• the elevated temperature of the flowable substance 20 (PVP melt) is maintained, while the pattern surface 31.1 has room temperature or a working temperature, which is set with the tempering device of the drawing device.
• the working temperature may differ from the room temperature.
• the tempering device can also be provided for cooling.
• a temperature gradient is thus given.
• hardening of the thread connection 22 already takes place during the separation movement starting from the adhesion islands 31.1.
• the surface tension of the material which is still flowable during drawing causes a minimum surface, which is characterized in particular by a taper of the thread connections 22 with increasing distance from the pattern surface 31.1.
• the pattern surface 31.1 and the flowable substance 20 By pulling the pattern surface 31.1 and the flowable substance 20, this adheres to the adhesive islands 32.
• the thread connections 22 (polymer threads) form whose starting points on the pattern surface 31.1 are predetermined by the arrangement of the adhesion islands 32 and whose orientation generally depends on the pulling direction of the pattern surface 31.1.
• the shape, length and other properties, such. B. mechanical and optical properties, can by the pulling rate and the physical properties of the substance 20, such as.
• Example 2 the composition, the molecular weight, the degree of crosslinking of the polymer, the viscosity or the viscoelastic properties of the substance 20 and by the rate of solidification (curing) of the substance can be determined.
• the concretely realized operating parameters may possibly be selected or optimized by experiments. With continued separation movement occurs according to FIG ID to a severing of the thread connections, so that the thread-like projections 11 remain on the pattern surface 31.1. The elevations from the fluid surface 21. 1 sink back into the dissolved or molten substance 20.
• FIGS. 2A to 2D show the corresponding method sequence according to the second embodiment of the invention. This differs from the first embodiment by providing the flowable substance 20 in the form of islands 36 on the pattern surface 31.2 and the formation of the opposite stamp surface as a solid surface 21.2.
• the sequence of movements analogous to the steps described above with reference to FIGS. 1A to 1B initially involves mutual contact of the stamp surface 21.2 and the pattern surface 31.2 with the islands 36 (FIG. 2B) and then a separation movement, so that the thread connections 22 are clamped ( Figure 2C). During the separation movement, the curing of the thread connections 22 takes place, whereby an interruption takes place in the region of the smallest diameter, so that the thread-like projections 11 remain on the stamp face 21.2 and / or the pattern face 31.2.
• the islands 36 are fixed on the pattern surface 31.2.
• the islands 36 comprise, for example, polystyrene particles with a diameter of 200 nm, which are connected by partial dissolution to the pattern surface 31.2 of polystyrene.
• the flowable substance 20 and the material of the pattern surface 31.2 are selected so that the melting temperature of the pattern surface 31.2 is higher than that of the flowable substance 20. This condition can advantageously be met with polymer particles in that the particulate islands 36 and the material of the pattern area 31.2 have the same chemical composition but different chain lengths of the polymers.
• the solid surface 21.2 is made of a metal (eg, copper, steel, or an alloy of these) whose temperature is raised during contact of the pattern and stamp surfaces to liquefy the flowable substance 20.
• the solid surface 21.2 may consist of a ceramic or glass.
• the thread-like projections preferably arise on the pattern surface 31.2.
• the flowable substance 20 and pattern surface 31 are chemically incompatible materials.
• particulate islands 36 of liquefiable polymer are deposited on a metal pattern surface 31.2 (eg, copper, steel, or an alloy of these). The islands 36 adhere to the pattern surface 31.2 without being chemically bonded thereto.
• the solid surface 21.2 consists of a material with which the flowable substance 20 can form a chemical compound.
• the flowable substance 20 is connected to the solid surface 21.2.
• the flowable substance 20 is heated over the pattern and / or solid surfaces.
• the compound of the flowable substance 20 with the solid surface 21.2 includes, for example, a partial melting or a chemical
• the component 100 according to the invention with the structured surface 10 comprises according to FIG. 3 as the base element 33 the pattern surface 31. 1 on which the thread-like projections 11 are arranged.
• 4 to 6 illustrate further variants of the component 100 according to the invention.
• the surface of the substance 20, eg by cooling or solvent removal is hardened while the thread connections 22 are pulled (see eg FIG that upon interruption of the thread connections thread-like projections 11 on the fixed base element 23 th form fluid surface.
• the base member 23 is stabilized on a carrier 24.
• the component 100 comprises the carrier 24 with the base element 23 and the thread-like projections 11.
• Figures 5 and 6 show further processing steps after the completion of the component 100.
• the generation of thickenings 12 at the free ends of the projections 11 is provided.
• the projections 11 are covered with a cover layer 13.
• This embodiment is of interest, for example, for optical applications of structured surfaces in which the projections 11 are to be protected from environmental influences.
• a processing step after the completion of the component 100 may alternatively or additionally comprise a hardening of the projections by irradiation.
• FIG. 7 illustrates a further variant of the invention, in which the projections 11 are formed in multiple layers.
• the method illustrated above is performed several times, wherein the respective projections formed are used as adhesion islands for the subsequent extraction of threads.
• the extension 14 of the projection 11 may be formed of the same material as the projection 11 or a different material.
• FIG. 8 schematically shows an apparatus 200 for producing a structured surface 10 of which, for reasons of clarity, a variant of the pattern surface 31.1 with only a single projection 11 on the adhesion island 32 is shown.
• the apparatus 200 comprises the drawing device 30 with the drive device 34 and the tempering device 35, a heating device 40 with a carrier or vessel 41 for receiving the flowable substance 20 and optionally one Conditioning device 50, with which the shape of the thread connections during the pulling operation and the projections 11 can be influenced.
• the drive device 34 serves to align and move the pattern surface 31.1.
• a stepper motor is provided.
• the tempering device 35 and the heater 40 include z. B. resistance heaters.
• the conditioning device 50 includes, for example, a magnet (permanent magnet or electromagnet) for generating a magnetic field under whose action a curvature of the projections 11 is formed.
• the substance 20 contains a magnetic additive substance, such as. B. magnetic colloids.
• an electric field for influencing the projection shape can be generated.
• a particular advantage of the invention is that the conditioning device 50 acts on all projections simultaneously, so that a uniform shaping can be achieved on all projections.
• the conditioning device 50 can be set up to chemically influence the shape of the projections 11.
• the structuring process with the pulling of the thread connections 22 according to FIG. 1 or 2 does not necessarily have to take place in a gaseous environment, but may alternatively also be provided in a liquid.
• the structuring according to the invention of a surface in a liquid has advantages compared to the process of a gaseous environment for the temperature control, the controllability of the escape of solvent from the drawn threads of the flowable substance and by the mechanical separation of the projections, in particular in projections with a high surface density.
• FIG. 9 illustrates by way of example the generation of curved projections 11 by a pulling direction deviating from the surface normal (see arrow).
• the separation movement takes place along a straight or curved reference line relative to the fluid surface 21.1.
• the pulling direction can be changed during the separation movement to influence the orientation and / or shape of the projections.
• Curved protrusions can be advantageously used for dynamically switchable surfaces, as illustrated schematically in FIG. If, for example, curved protrusions according to FIG. 9 are made of PVP in a neutral surrounding medium, they are directed by a change in the pH in an acidic medium. A corresponding switching movement can also be achieved by a temperature change. This switching may be of interest for optical or sensor applications of structured surfaces.
• FIG. 11 shows various variants of adhesion islands in a schematic plan view.
• base surfaces 32A, 32B in order to produce mechanical anisotropies of the structured surface, in particular base surfaces with one or more preferred directions, such as, for example, can be used.
• Reference numeral 32E exemplifies dot-shaped adhesion islands. If the adhesion islands alternatively have bases with more than four corners, advantages for the mechanical stability of the fibers drawn according to the invention may result.
• FIGS. 11 to 14 illustrate electron microscopic images of surface structures of polyvinylpyridine prepared according to the invention. According to FIG. 14, according to the invention, even projections with turns are produced, which in the case of FIG. 14, according to the invention, even projections with turns are produced, which in the case of FIG. 14, according to the invention, even projections with turns are produced, which in the case of FIG. 14, according to the invention, even projections with turns are
• Curing of polymers can form during an extreme shearing motion.
• FIG. 15 schematically shows details of a further embodiment of an apparatus 201 for producing a structured surface 10 with curved projections 11.
• This embodiment is particularly suitable for the production of continuous material with a surface structured according to the invention.
• the apparatus 201 includes a roller 42, which is immersed in the vessel 41 with the flowable substance 20 and outside of the vessel 41, the pattern surface 31.1 touches with the adhesive island 32.
• the heating device for the vessel 41 and / or the roller 42 and the optional conditioning device are not shown.
• a drive device for example a motor, not shown
• a drive device is provided to move the pattern surface 31.1 in the direction of the arrow, thereby rotating the roller 42.
• a layer of the flowable substance 20 is formed on its cylindrical surface, the free fluid surface facing the sample surface 31.1.
• the adhesive island 32 relative to the fluid surface of the flowable substance 20 perform a shearing motion, with which the shape of the thread connections during the pulling process and the projections 11 (shown enlarged) can be influenced.
• the pattern surface 31.1 can be arranged on a carrier as shown, or alternatively be guided past the roller 42 with another roller.

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• 2006
  • 2006-02-20 DE DE102006007800A patent/DE102006007800B3/de not_active Expired - Fee Related
• 2007
  • 2007-02-14 JP JP2008554671A patent/JP2009527373A/ja active Pending
  • 2007-02-14 CN CN200780006018.0A patent/CN101384505B/zh not_active Expired - Fee Related
  • 2007-02-14 WO PCT/EP2007/001285 patent/WO2007096082A1/de active Application Filing
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