WO2010059127A1 - A portable electrospinning apparatus - Google Patents

A portable electrospinning apparatus Download PDF

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Publication number
WO2010059127A1
WO2010059127A1 PCT/SG2008/000444 SG2008000444W WO2010059127A1 WO 2010059127 A1 WO2010059127 A1 WO 2010059127A1 SG 2008000444 W SG2008000444 W SG 2008000444W WO 2010059127 A1 WO2010059127 A1 WO 2010059127A1
Authority
WO
WIPO (PCT)
Prior art keywords
hollow elongate
elongate device
fibres
electrospinning
outlet
Prior art date
Application number
PCT/SG2008/000444
Other languages
French (fr)
Inventor
Ying Jun Liu
Ramakrishnan Ramaseshan
Yi Xiang Dong
Abhishek Kumar
Seeram Ramakrishna
Original Assignee
National University Of Singapore
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by National University Of Singapore filed Critical National University Of Singapore
Priority to PCT/SG2008/000444 priority Critical patent/WO2010059127A1/en
Publication of WO2010059127A1 publication Critical patent/WO2010059127A1/en

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Classifications

    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
    • D01D5/00—Formation of filaments, threads, or the like
    • D01D5/0007—Electro-spinning
    • D01D5/0061—Electro-spinning characterised by the electro-spinning apparatus
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
    • D01D5/00—Formation of filaments, threads, or the like
    • D01D5/0007—Electro-spinning
    • D01D5/0061—Electro-spinning characterised by the electro-spinning apparatus
    • D01D5/0076—Electro-spinning characterised by the electro-spinning apparatus characterised by the collecting device, e.g. drum, wheel, endless belt, plate or grid
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
    • D01D5/00—Formation of filaments, threads, or the like
    • D01D5/0007—Electro-spinning
    • D01D5/0061—Electro-spinning characterised by the electro-spinning apparatus
    • D01D5/0076—Electro-spinning characterised by the electro-spinning apparatus characterised by the collecting device, e.g. drum, wheel, endless belt, plate or grid
    • D01D5/0084—Coating by electro-spinning, i.e. the electro-spun fibres are not removed from the collecting device but remain integral with it, e.g. coating of prostheses

Definitions

  • a portable electrospinning apparatus A portable electrospinning apparatus
  • the present invention provides a portable electrospinning apparatus.
  • the apparatus may comprise a hollow elongate device capable of directing electrospun fibres towards a particular direction.
  • the present invention also provides a flexible construct for grounding at least one surface.
  • WO 02/074191 describes a portable electrospinning device.
  • the device described in WO 02/074191 has problem of solvent exposure to the user, which may be harmful to the user. This also limits and blocks the application of the technology.
  • the present invention seeks to address the problems above, and provides a hollow elongate device which is capable of directing electrospun fibres towards a particular direction and/or orientation.
  • the present invention provides a portable electrospinning apparatus for generating fibres, the apparatus comprising: at least one reservoir for holding at least one electrospinning medium;
  • a hollow elongate device adapted to connect to the outlet, the hollow elongate device being capable of directing the dispensed fibres towards a pre-determined direction.
  • the dispensed fibres may be directed towards a pre-determined direction and/or orientation towards the surface onto which the fibres are deposited.
  • the hollow elongate device may be made of any suitable material.
  • at least a part of the hollow elongate device may be made of at least one dielectric material.
  • the dielectric material may be any one of, but not limited to, ceramics, refractory materials such as metal oxides, oil- impregnated paper, pressboard, mica, elastomers, press-moulded resins, polyethylene, polypropylene, polystyrene, polytetrafluoroethylene, polyvinyl chloride, polymethyl methacrylate, polyamide, polyimide, porcelain, polysilicates, polyalkenes, polyxylenes, silicones, polytetrafluoroethylene and mixtures thereof.
  • the hollow elongate device has an inner surface and an outer surface, and wherein the inner surface may be coated and/or layered with at least one adsorbent material.
  • the layering of the inner surface may be in the form of a padding of at least one adsorbent material on the inner surface.
  • Any suitable adsorbent material may be used for the purposes of the present invention.
  • the adsorbent material may be any one of, but not limited to, laminated charcoal, silica gel, dessicants, synthetic resins, naturally occurring resins, and mixture thereof.
  • the hollow elongate device according to any aspect of the present invention may be of any suitable shape.
  • the hollow elongate device may comprise a first end and a second end, the first end being adapted to connect to the outlet.
  • the hollow elongate device may be conical shaped.
  • the hollow elongate device may be conical shaped and the diameter of the hollow elongate member may increase from the first end to the second end.
  • the hollow elongate device comprises further extensions capable of further directing the dispensed fibres towards the pre-determined direction and/or orientation.
  • the further extensions may be in any suitable form.
  • the further extensions may comprise at least two arms.
  • the further extensions may be flexible.
  • the extensions may comprise at least two arms and the arms may be flexed and/or adjusted to control the angle formed between two adjacent arms.
  • the further extensions comprise at least two arms and form an angle of ⁇ 180° between two adjacent arms.
  • the hollow elongate device may comprise a telescoping assembly comprising at least two members, wherein the first member is co-operatively engaged with the second member.
  • a second aspect of the present invention provides a hollow elongate device arranged to be connected to an outlet of a portable electrospinning apparatus for dispensing electrospun fibres, the hollow elongate device being capable of directing the dispensed fibres towards a pre-determined direction and/or orientation.
  • the fibres dispensed from the outlet of the portable electrospinning apparatus may be deposited onto a surface.
  • the dispensed fibres may be directed towards a pre-determined direction and/or orientation towards the surface onto which the fibres are deposited.
  • the present invention also provides a construct for grounding at least one surface, the construct arranged to be contacted with the at least one surface on which electrospun fibres are deposited, wherein the construct is flexible to substantially conform to the shape of the at least one surface.
  • the construct may be for use with an electrospinning apparatus. Any suitable electrospinning apparatus may be used. In particular, the electrospinning apparatus may be as described above.
  • the construct may comprise at least one conductive structure with a flexible connection.
  • the conductive structure may be a metal structure.
  • the structure may be at least one wire, rod, tube and/or pipe.
  • Figure 1 A side plan view of an electrospinning apparatus according to one embodiment of the present invention.
  • Figure 2 A hollow elongate device according to one embodiment of the present invention.
  • Figure 3 A hollow elongate device according to one embodiment of the present invention.
  • Figure 4 A schematic representation of an electrospinning apparatus according to one embodiment of the present invention.
  • Figure 5 A side plan view of an electrospinning apparatus according to one embodiment of the present invention.
  • FIG 6 A circuit diagram of the circuit in an electrospinning apparatus according to another embodiment of the present invention.
  • HV refers to a high voltage generator and
  • FAN refers to a fan to direct the fibres being expelled from the outlet of the electrospinning apparatus.
  • Figure 7 A hollow elongate device according to a second embodiment of the present invention.
  • the portable electrospinning device may be used in households by individuals as well as in small-scale industries and research.
  • a first aspect of the present invention is a portable electrospinning apparatus for generating fibres.
  • the apparatus comprises:
  • portable electrospinning apparatus is defined as an apparatus used for electrospinning which can be easily carried and moved or transported from one place to another.
  • the portable electrospinning apparatus according to the present application may be a hand- held electrospinning apparatus such that the apparatus is small and/or light enough to be operated while being held in a user's hands.
  • the hollow elongate device may be adapted to connect to the outlet of the electrospinning apparatus by any suitable connection.
  • the hollow elongate device may be connected to the outlet by frictional contact between the hollow elongate device and the outlet.
  • the outlet may comprise connection means to allow the hollow elongate device to connect to the outlet of the electrospinning apparatus.
  • the connection means may comprise an O-ring at an interface between the outlet and the hollow elongate member.
  • the connection means may also comprise a locking mechanism between the outlet and the hollow elongate member.
  • the locking mechanism may comprise any one or a combination of a press-fit, interference fit or spring loaded mechanism.
  • the connection means may also comprise an adhesive for adhering the hollow elongate device to the outlet of the electrospinning apparatus.
  • the adhesive may be a layer of glue or any other suitable means of adhering two surfaces together.
  • the hollow elongate member may be connected to the outlet of the electrospinning apparatus permanently or may be releasably removable from the outlet of the electrospinning apparatus.
  • At least a part of the hollow elongate member may be made of at least one dielectric material.
  • the dielectric material may be selected from the group consisting of: ceramics, refractory materials such as metal oxides, oil- impregnated paper, pressboard, mica, elastomers, press-moulded resins, polyethylene, polypropylene, polystyrene, polytetrafluoroethylene, polyvinyl chloride, polymethyl methacrylate, polyamide, polyimide, porcelain, polysilicates, polyalkenes, polyxylenes, silicones, polytetrafluoroethylene and mixtures thereof.
  • the polysilicates may be in the form of mica sheets or slices.
  • the dielectric material may protect a user of the electrospinning apparatus from high voltage and focus the deposition of the electrospun fibre by expulsion from the outlet of the electrospinning apparatus to the surface onto which the fibres are deposited.
  • the hollow elongate device has an inner surface and an outer surface. According to a particular aspect, at least a part of the inner surface of the hollow elongate device may be coated and/or layered with at least one adsorbent material.
  • the layering of the inner surface may be in the form of a padding of at least one adsorbent material on the inner surface.
  • the adsorbent material may adsorb the evaporating solvent expelled from the outlet of the electrospinning apparatus during the electrospinning process. In this way, the user is protected from the evaporating solvent, especially when the solvent may be considered to be toxic or hazardous to the user. Solvent exposure to the user is also reduced. Any suitable adsorbent material may be used.
  • the adsorbent material may be selected from the group consisting of: laminated charcoal, silica gel, dessicants, synthetic resins, naturally occurring resins, and mixtures thereof.
  • the dessicants may be calcium chloride or calcium sulphate.
  • the hollow elongate device may be of any suitable shape and size.
  • the hollow elongate device may comprise a first end and a second end, the first end being adapted to connect to the outlet of the electrospinning apparatus.
  • the hollow elongate device may be conical shaped.
  • the diameter of the hollow elongate device may increase from the first end to the second end.
  • the hollow elongate device may keep away the turbulence and maintain an electrospinning jet during the electrospinning process.
  • the hollow elongate device may comprise further extensions capable of further directing the dispensed fibres towards the pre-determined direction and/or orientation. The further extensions may be flexible.
  • the further extensions may be in the form of at least two arms.
  • the angle between two adjacent arms may be adjusted to ⁇ 180°.
  • the angle between two adjacent arms may be adjusted according to the area of the surface onto which the electrospun fibres are deposited. For example, if it is desired to coat only a part of a surface of a substrate, the angle between two adjacent arms of the hollow elongate device may be adjusted such that the electrospun fibres are directed towards that part of the surface of the substrate. In particular, if a wider area of the surface of the substrate is to be coated with the deposited electrospun fibres, the two adjacent arms may be adjusted to form a larger angle. In contrast, if a smaller area of the surface of the substrate is to be coated with the deposited electrospun fibres, the two adjacent arms may be adjusted to form a smaller angle.
  • FIG. 1 shows an electrospinning apparatus 100.
  • Electrospinning apparatus 100 has an outlet 101 from which electrospun fibres 106 are dispensed onto a grounded substrate surface 104.
  • a hollow elongate device 102 is connected to outlet 101 of electrospinning apparatus 100.
  • hollow elongate device 102 may be in the form of a cone.
  • Figure 2 shows a hollow elongate device connected to an outlet 201 of an electrospinning apparatus (not shown) having two extensions, 202a and 202b.
  • Extensions 202a and 202b which are flexible, can be adjusted in the direction indicated by the arrows in Figure 2. Accordingly, the angle ⁇ between extensions 202a and 202b can be adjusted depending on the area of the surface which is to be coated by the deposited electrospun fibres, as explained above.
  • the hollow elongate device may also comprise a telescoping assembly comprising at least two members, wherein the first member is co-operatively engaged with the second member.
  • a telescoping assembly refers to members that fit together like a set of cylinders that slide into one another, allowing extension and shortening of the assembly.
  • the telescoping assembly may contain any number of members, with a minimum of two members and wherein the first member is co-operatively engaged with the second member. The number of members may vary depending on the length desired to extend the device to.
  • Figure 3 shows a hollow elongate device 300 connected to an outlet 301 of an electrospinning apparatus (not shown).
  • the hollow elongate device 300 comprises a telescoping assembly comprising three pairs of extensions members, 302a and 302b; 304a and 304b; and 306a and 306b.
  • members 302a, 304a and 306a are all co-operatively engaged with the adjacent member.
  • 302b, 304b and 306b are all co-operatively engaged with the adjacent member.
  • member 302a is co-operatively engaged with member 304a, which is in turn co-operatively engaged with member 306a.
  • the at least one reservoir may be for holding at least one electrospinning medium.
  • the reservoir may be a container.
  • the container may be replaceable.
  • the medium may be any medium suitable for electrospinning.
  • the electrospinning medium may be a solution comprising at least one polymer.
  • Any suitable polymer may be used for the purposes of the present invention.
  • the polymer may be a hydrophilic polymer, a hydrophilic polymer and/or an amphiphilic polymer.
  • the polymer may be selected from the group consisting of: polyamide, polyester, polyacrylate, polysulfone and fluoropolymers.
  • the polymer may be selected from the group consisting of: polycaprolactone, polyamides, polyimides, polycarbamides, polyolefins, polyurethanes, polyethylene oxide, polylactide, poly-L-lactic acid, polygyycolide, poly(glycolic acid), polyesters, poly(vinylidene fluoride), poly(vinylidene fluoride-co-hexafluoropropylene), poly(DL-lactide), poly(L-lactide), polydioxanone, chitin, collagen either in its native form or cross-linked, silk, chitosan, poly(glutamic-co-leucine), poly-lactic- glycolide acid, poly(L-lactic acid-caprolactone), polyacrylonitrile, poly(acrylonitrile-co-methacrylate), polymethylmethacrylate, polyvinylchloride, poly(vinylidenechloride-co-acrylate), polyethylene, polypropylene
  • the electrospinning medium may also comprise at least one solvent for dissolving the polymer.
  • Any suitable solvent may be used.
  • the solvent may be an organic or an inorganic solvent.
  • the solvent may be selected according to the polymer used. Examples of suitable solvents which can be used in combination with different polymers are provided in Cheng-Ming Huang et al, Composites Science and Technology, 63:2223-2253, 2003.
  • the solvent may be an aqueous based solvent.
  • the solvent may be acetic acid.
  • the solvent when the polymer is poly(ethylene oxide) or polyvinyl alcohol), the solvent may be water; when the polymer is collagen, the solvent may be hydrochloric acid; when the polymer is cellulose acetate, the solvent may be acetic acid; and when the polymer is polyvinyl pyrrolidone), the solvent may be ethanol and/or acetic acid.
  • the power supply for powering the apparatus may be any suitable power supply.
  • the power supply may be a high voltage supply.
  • the power supply may be a low DC high voltage power supply.
  • the power may be supplied by at least one battery.
  • the battery may be at least one AA battery.
  • the outlet of the electrospinning apparatus may in any suitable form.
  • the outlet of the electrospinning apparatus may be a spinneret with a needle.
  • the needle may be a metallic needle.
  • the outlet of the electrospinning apparatus may be connected to the power supply of the electrospinning apparatus.
  • the electrospinning apparatus may further comprise at least one pump.
  • Any suitable pump may be used for the purposes of the present invention.
  • the pump may be a battery-powered pump, a manually pressured pump or a motorized fluidic pump.
  • the pump may be a syringe pump.
  • the pump may be used for pumping electrospinning medium from the reservoir to the outlet of the electrospinning apparatus.
  • the pump pumps the electrospinning medium from the reservoir to the needle tip of the outlet of the electrospinning apparatus, forming a droplet at the tip.
  • the electrospinning apparatus also comprises a grounded electrode.
  • the grounded electrode is suitable for contacting a surface onto which the electrospun fibres are deposited.
  • the surface onto which the electrospun fibres are deposited are grounded so that a potential difference is formed between the outlet of the electrospinning apparatus and the surface.
  • the grounded electrode may be flexible to substantially conform to the shape of the at least one surface onto which the electrospun fibres are deposited.
  • the shape of the grounded electrode may be adjusted to substantially conform to the shape of the surface onto which the electrospun fibres are to be deposited to adjust the local electric, magnetic, fluidic and temperature field near the grounded surface so that a more efficient coating is achieved over the entire grounded surface.
  • the grounded electrode may comprise at least one conductive structure with a flexible connection.
  • the conductive structure may be a metal structure.
  • the structure may be at least one wire, rod, tube and/or pipe.
  • FIG. 4 shows an electrospinning apparatus 400 powered by power supply 402.
  • Power supply 402 may consist of AA batteries.
  • Electrospinning apparatus 400 may comprise a reservoir 404 for holding polymer solution 406 which is used as the electrospinning medium.
  • Polymer solution 406 may be pumped from reservoir 404 to outlet 410 of electrospinning apparatus 400 by any suitable means.
  • Polymer solution 406 is pumped from reservoir 404 to outlet 410 by pump 408.
  • Pump 408 may be battery-powered or manually pressured.
  • a hollow elongate device 412 as described above may be connected to outlet 410.
  • a grounded electrode 414 may also be connected to power supply 402.
  • Grounded electrode 414 is placed on the surface of a substrate (not shown) which is to be coated by electrospun fibres formed from electrospinning apparatus 400.
  • Electrospinning apparatus 400 may comprise a housing 416 which encloses power supply 402, reservoir 404 and pump 408.
  • FIG. 5 shows a side plan view of one embodiment of an electrospinning apparatus of the present invention.
  • Figure 5 shows an electrospinning apparatus 500 comprising a housing 502 which comprises reservoir 504 holding the electrospinning medium, a power supply (not shown) and pump (not shown). There is also provided a power button 516 which upon user intervention completes the power circuit within apparatus 500 and starts the electrospinning process.
  • Electrospinning apparatus 500 also comprises an outlet 506 from which the electrospun fibres are dispensed.
  • a hollow elongate device 508 is connected to outlet 506.
  • Electrospun fibres 514 are dispensed from outlet 506 onto substrate surface 512 which is grounded by ground electrode 510.
  • Electrospinning uses an electrical charge to form a mat of fine fibres. Electrospinning shares characteristics of both the commercial electro-spray technique and the commercial spinning of fibres.
  • the standard setup for electrospinning consists of a spinneret with a metallic needle, a syringe pump, a high-voltage power supply, and a grounded collector.
  • a polymer, sol-gel, composite solution (or melt) is loaded into the syringe and this liquid is driven to the needle tip by a syringe pump, forming a droplet at the tip.
  • a voltage is applied to the needle, the droplet is first stretched into a structure called the Taylor cone.
  • the electrospinning process will be described with reference to Figure 5.
  • the reservoir 504 may be connected to a pump (not shown) which pumps electrospinning medium from the reservoir 504 towards outlet 506 of electrospinning apparatus 500.
  • Outlet 506 may consist of a single spinneret, multiple spinnerets, co-axial spinneret, bi-capillary spinneret, multi-capillary spinneret.
  • the spinneret of outlet 506 is used to deliver a constant supply of the at least one electrospinning medium.
  • a high voltage from a power supply (not shown) is applied to the at least one electrospinning medium at the spinneret of outlet 506.
  • a jet of solution 514 of the medium is ejected from the tip of the spinneret of outlet 506 through hollow elongate device 508 and accelerate towards a surface 512 of a substrate.
  • the surface 512 onto which the electrospinning jet 514 is collected may be grounded by a ground electrode 510 so that the electrospinning jet 514 is more readily deposited on surface 512.
  • the solvent from the electrospinning jet 514 collected may evaporate upon cooling, or extracted by a suitable non-solvent on the surface 512, thereby forming fibres.
  • the electrospinning medium is extruded from reservoir 504, for example using a pump, or under the action of gravity, through a minute capillary aperture.
  • a process of solvent evaporation or cooling or extraction starts, which is accompanied by the creation of capsules with a semi-rigid envelope or crust, otherwise known as the Taylor cone.
  • An electric field is generated by the potential difference between the extruder and precipitation surface 512. Because the electrospinning medium possesses a certain degree of electrical conductivity, the capsules become charged. Electric forces of repulsion between the molecular chains within the capsules lead to a drastic increase in hydrostatic pressure.
  • the semi-rigid envelopes are stretched, and a number of point micro-ruptures are formed on the surface of each envelope leading to spraying of ultra-thin jets 514 of liquefied polymer from outlet 506.
  • the jets 514 depart from the outlet 506 and travel towards the opposite precipitation surface 512, which is always grounded by ground electrode 510.
  • the jet 514 cools or solvent therein evaporates, or extracted by any suitable non-solvent on the precipitation surface 512, thus forming fibres which are collected on the precipitation surface 512.
  • the flow-rate of the electrospinning medium may vary from 0.1 ml_/hour to 10 mL/hour.
  • the reservoir of the electrospinning apparatus according to the present invention may be exchangeable so that a reservoir containing another electrospinning medium may be used. In this way, it is convenient to switch from one kind of electrospinning medium to another to meet different applications.
  • the reservoir may also be disposable.
  • the outlet of the electrospinning apparatus may be connected to the power supply at either the positive or negative electrode of the power supply.
  • the polymer micro/nano fibre will be drawn from the outlet and preferable deposited towards the direction of grounded electrode by electric field force.
  • the polymer micro/nano fibre may be drawn from the outlet and through a hollow elongate device which is connected to the outlet.
  • the grounded electrode may be contacted with the coating target which can be any substantial item.
  • the grounded electrode may comprise several conductive structures with a flexible connection.
  • the conductive structure may be a metal structure.
  • the structure may be at least one wire, rod, tube and/or pipe. In this way, the grounded electrode may be easily adjusted to fit the proper size and shape of the target.
  • the grounded electrode of the electrospinning apparatus is adjusted to fit the shape of the coating target and is subsequently attached to the target.
  • a reservoir with the desired electrospinning medium is provided to the electrospinning apparatus.
  • the circuit within the electrospinning apparatus is completed, which triggers the pump to start and high voltage supply to generate polymer nano/micro fibres by forming the fibre jets which are dispensed through the outlet of the electrospinning apparatus.
  • a hollow elongate device may be connected to the outlet from which the fibre jets are dispensed. The hollow elongate device may be as described above.
  • the hollow elongate device is adjusted to get a desired coating profile as described above.
  • the electrospinning apparatus may further comprise a fan or a blower to generate airflow substantially directed towards the outlet of the electrospinning apparatus.
  • a circuit diagram of the electrospinning apparatus is shown in Figure 6.
  • the electrospinning apparatus may also comprise a dehumidifier to improve the electrospinning environment.
  • the electrospinning apparatus may further comprise a combination of needle and cartridge as shown in Figure 7.
  • Figure 7 shows an electrospinning apparatus 700 comprising needle 702 and cartridge unit 704.
  • Cartridge unit 704 comprises a needle 706, a syringe 708 which holds electrospinning medium 710. Needle 706 is of a suitable size such that needle 706 can be inserted into needle 702. Needle 706 may be fully or partially inserted into needle 701.
  • the cartridge unit 704 is inserted into the needle 701 from the front.
  • the base of the cartridge unit 704 may be metallic to be used for electrospinning.
  • Voltage supply 714 is connected to needle 701.
  • the voltage supply 714 may be high voltage supply.
  • a pump 712 is then used to inject the electrospinning medium 710 into needle 702. Alternatively, a force may be applied on syringe 708.
  • the cartridge unit 704 may be removed and replaced with another cartridge unit. In this way, different electrospinning medium may be easily loaded into the electrospinning apparatus 700.
  • Cartridge unit 704 may be disposable or reusable.
  • the electrospinning apparatus may be an electrospinning apparatus used for generating a fibrous network or fibrous structure from an electrospinning medium.
  • the electrospinning medium may be a polymer solution.
  • the fibrous structure may be in the form of a coating.
  • the coating may be used for painting, as a water repelling coating, an insulation coating, a coating to inhibit growth of microorganisms, wound healing, wound dressing, tissue regeneration and other suitable applications in which a coating or spray device is used.
  • the fibrous structures may also be used for solid, liquid and/or gas filtration applications,
  • the electrospinning apparatus according to the present invention may be in the shape of a gun.
  • the electrospinning apparatus may be suitable for household applications or small-scale industrial use.
  • Another aspect of the present invention is a hollow elongate device arranged to be connected to an outlet of an electrospinning apparatus for dispensing electrospun fibres, the hollow elongate device being capable of directing the dispensed fibres towards a pre-determined direction and/or orientation.
  • the hollow elongate device may be connected to the outlet of any electrospinning apparatus.
  • the electrospinning apparatus may be a portable electrospinning apparatus. Even more in particular, the electrospinning apparatus may be the electrospinning apparatus as described above.
  • the hollow elongate device may be adapted to connect to an outlet of an electrospinning apparatus by any suitable connection.
  • the hollow elongate device may be connected to the outlet by frictional contact between the hollow elongate device and the outlet.
  • the outlet may comprise connection means to allow the hollow elongate device to connect to the outlet of the electrospinning apparatus.
  • the connection means may comprise an O-ring at an interface between the outlet and the hollow elongate member.
  • the connection means may also comprise a locking mechanism between the outlet and the hollow elongate member.
  • the locking mechanism may comprise any one or a combination of a press-fit, interference fit or spring loaded mechanism.
  • connection means may also comprise an adhesive for adhering the hollow elongate device to the outlet of the electrospinning apparatus.
  • the adhesive may be a layer of glue or any other suitable means of adhering two surfaces together.
  • the hollow elongate member may be connected to the outlet of the electrospinning apparatus permanently or may be releasably removable from the outlet of the electrospinning apparatus.
  • At least a part of the hollow elongate member may be made of at least one dielectric material.
  • the dielectric material may be selected from the group consisting of: ceramics, refractory materials such as metal oxides, oil- impergnated paper, pressboard, mica, elastomers, press-moulded resins, polyethylene, polypropylene, polystyrene, polytetrafluoroethylene, polyvinyl chloride, polymethyl methacrylate, polyamide, polyimide, porcelain, polysilicates, polyalkenes, polyxylenes, silicones, polytetrafluoroethylene and mixtures thereof.
  • the polysilicates may be in the form of form of mica sheets or slices.
  • the dielectric material may protect a user of the electrospinning apparatus from high voltage and focus the deposition of the electrospun fibre by expulsion from the outlet of the electrospinning apparatus to the surface onto which the fibres are deposited.
  • the hollow elongate device has an inner surface and an outer surface. According to a particular aspect, at least a part of the inner surface of the hollow elongate device may be coated and/or layered with at least one adsorbent material.
  • the layering of the inner surface may be in the form of a padding of at least one adsorbent material on the inner surface.
  • the adsorbent material may adsorb the evaporating solvent expelled from the outlet of the electrospinning apparatus during the electrospinning process. In this way, the user is protected from the evaporating solvent, especially when the solvent may be considered to be toxic or hazardous to the user. Any suitable adsorbent material may be used.
  • the adsorbent material may be selected from the group consisting of: laminated charcoal, silica gel, dessicants, synthetic resins, naturally occurring resins, and mixtures thereof.
  • the dessicants may be calcium chloride or calcium sulphate.
  • the hollow elongate device according to the present invention may be of any suitable shape and size.
  • the hollow elongate device may comprise a first end and a second end, the first end being adapted to connect to the outlet of the electrospinning apparatus.
  • the hollow elongate device may be 5-20 cm in length and/or 2-25 cm in diameter.
  • the hollow elongate device may be conical shaped.
  • the diameter of the hollow elongate device may increase from the first end to the second end.
  • the hollow elongate device may keep away the turbulence and maintain an electrospinning jet during the electrospinning process.
  • the hollow elongate device may be useful for blocking out strong winds and high humidity from the fibres which are dispensed from the outlet of the electrospinning apparatus.
  • the hollow elongate device may comprise further extensions capable of further directing fibres dispensed from an outlet of an electrospinning apparatus towards the pre-determined direction.
  • the further extensions may be flexible.
  • the further extensions may be in the form of at least two arms.
  • the angle between two adjacent arms may be adjusted to ⁇ 180°.
  • the angle between two adjacent arms may be adjusted according to the area of the surface onto which the electrospun fibres are deposited. For example, if it is desired to coat only a part of a surface of a substrate, the angle between two adjacent arms of the hollow elongate device may be adjusted such that the electrospun fibres are directed towards that part of the surface of the substrate.
  • the two adjacent arms may be adjusted to form a larger angle.
  • the two adjacent arms may be adjusted to form a smaller angle.
  • Figure 1 shows a hollow elongate device 102 connected to an outlet 101 of an electrospinning apparatus 100. Electrospun fibres 106 are dispensed from the outlet 101 onto a grounded substrate surface 104.
  • hollow elongate device 102 is in the form of a cone.
  • Figure 2 shows a hollow elongate device connected to an outlet 201 of an electrospinning apparatus (not shown) having two extensions, 202a and 202b.
  • Extensions 202a and 202b which are flexible, can be adjusted in the direction indicated by the arrows in Figure 2. Accordingly, the angle ⁇ between extensions 202a and 202b can be adjusted depending on the area of the surface which is to be coated by the deposited electrospun fibres, as explained above.
  • the hollow elongate device may also comprise a telescoping assembly comprising at least two members, wherein the first member is co-operatively engaged with the second member.
  • a telescoping assembly refers to members that fit together like a set of cylinders that slide into one another, allowing extension and shortening of the assembly.
  • the telescoping assembly may contain any number of members, with a minimum of two members and wherein the first member is co-operatively engaged with the second member. The number of members may vary depending on the length desired to extend the device to.
  • Figure 3 shows a hollow elongate device 300 connected to an outlet 301 of an electrospinning apparatus (not shown).
  • the hollow elongate device 300 comprises a telescoping assembly comprising three pairs of extensions members, 302a and 302b; 304a and 304b; and 306a and 306b.
  • members 302a, 304a and 306a are all co-operatively engaged with the adjacent member.
  • 302b, 304b and 306b are all co-operatively engaged with the adjacent member.
  • member 302a is co-operatively engaged with member 304a, which is in turn co-operatively engaged with member 306a.
  • Another aspect of the present invention is a construct for grounding at least one surface on which electrospun fibres are deposited, wherein the construct is flexible to substantially conform to the shape of the at least one surface.
  • the construct may be for use with an electrospinning apparatus.
  • the electrospinning apparatus may be a portable electrospinning apparatus. Even more in particular, the electrospinning apparatus may be the electrospinning apparatus as described above.
  • the construct may be a grounded electrode.
  • the construct may be suitable for contacting a surface onto which fibres dispensed from an electrospinning apparatus are deposited.
  • the surface onto which the electrospun fibres are deposited are grounded so that a potential difference is formed between an outlet of the electrospinning apparatus from which fibres are dispensed and the surface.
  • the construct may be flexible to substantially conform to the shape of the at least one surface onto which electrospun fibres are deposited.
  • the shape of the construct may be adjusted to substantially conform to the shape of the surface onto which the electrospun fibres are to be deposited to adjust the local electric, magnetic, fluidic and temperature field near the grounded surface so that a more efficient coating is achieved over the entire grounded surface.
  • a more targeted deposition of the electrospun fibres may also be achieved when the entire surface is grounded by the construct. In this way, non-metallic surfaces may be completely grounded since the construct can be conformed into the shape of the surface.
  • the construct may comprise at least one conductive structure with a flexible connection.
  • the conductive structure may be a metal structure.
  • the structure may be at least one wire, rod, tube and/or pipe.
  • the construct may be contacted with the coating target which can be any substantial item.
  • the construct may comprise several conductive structures with a flexible connection.
  • the conductive structure may be a metal structure which could be easily adjusted to fit the proper size and shape of the target.
  • the structure may be at least one wire, rod, tube and/or pipe. The temperature of the construct is also maintained by the conductive structures.
  • the construct may be made of any suitable material.
  • the material may be selected from the group consisting of: metal, semiconductor, ceramic, and mixtures thereof.
  • the material of the construct may be the same as or similar to the material from which the hollow elongate device is made.

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Abstract

The present invention provides a portable electrospinning apparatus for generating fibres comprising: at least one reservoir for holding at least one reservoir for holding at least one electrospinning medium; an outlet for dispensing the electrospun fibres; a grounded electrode for contacting a surface onto which the fibres are deposited; and a hollow elongate device adapted to connect to the outlet, the hollow elongate device being capable of directing the dispensed fibres towards a pre-determined direction. The present invention also provides a construct for grounding at least one surface, wherein the construct is flexible to substantially conform to the shape of the at least one surface.

Description

A portable electrospinning apparatus
Field of the invention
The present invention provides a portable electrospinning apparatus. In particular, the apparatus may comprise a hollow elongate device capable of directing electrospun fibres towards a particular direction. The present invention also provides a flexible construct for grounding at least one surface.
Background of the invention
Existing electrospinning apparatus are generally of a standing arrangement and restricted to laboratory and industrial usage. This arrangement is non-portable and cumbersome to use. Moreover, it is a standstill arrangement and it is difficult to move from one place to another.
WO 02/074191 describes a portable electrospinning device. However, the device described in WO 02/074191 has problem of solvent exposure to the user, which may be harmful to the user. This also limits and blocks the application of the technology.
Another electrospinning device is described in US 6,753,454. However, a user of the device described in US 6,753,454 would still be faced with solvent exposure.
There is therefore a need in the art for an improved electrospinning apparatus.
Summary of the invention
The present invention seeks to address the problems above, and provides a hollow elongate device which is capable of directing electrospun fibres towards a particular direction and/or orientation. In particular, the present invention provides a portable electrospinning apparatus for generating fibres, the apparatus comprising: at least one reservoir for holding at least one electrospinning medium;
an outlet for dispensing the electrospun fibres;
a grounded electrode for contacting a surface onto which the fibres are deposited; and
a hollow elongate device adapted to connect to the outlet, the hollow elongate device being capable of directing the dispensed fibres towards a pre-determined direction.
The dispensed fibres may be directed towards a pre-determined direction and/or orientation towards the surface onto which the fibres are deposited.
The hollow elongate device may be made of any suitable material. For example, at least a part of the hollow elongate device may be made of at least one dielectric material. In particular, the dielectric material may be any one of, but not limited to, ceramics, refractory materials such as metal oxides, oil- impregnated paper, pressboard, mica, elastomers, press-moulded resins, polyethylene, polypropylene, polystyrene, polytetrafluoroethylene, polyvinyl chloride, polymethyl methacrylate, polyamide, polyimide, porcelain, polysilicates, polyalkenes, polyxylenes, silicones, polytetrafluoroethylene and mixtures thereof.
According to a particular aspect, the hollow elongate device has an inner surface and an outer surface, and wherein the inner surface may be coated and/or layered with at least one adsorbent material. The layering of the inner surface may be in the form of a padding of at least one adsorbent material on the inner surface. Any suitable adsorbent material may be used for the purposes of the present invention. For example, the adsorbent material may be any one of, but not limited to, laminated charcoal, silica gel, dessicants, synthetic resins, naturally occurring resins, and mixture thereof. The hollow elongate device according to any aspect of the present invention may be of any suitable shape. According to a particular aspect, the hollow elongate device may comprise a first end and a second end, the first end being adapted to connect to the outlet. In particular, the hollow elongate device may be conical shaped. Even more in particular, the hollow elongate device may be conical shaped and the diameter of the hollow elongate member may increase from the first end to the second end.
According to another particular aspect, the hollow elongate device comprises further extensions capable of further directing the dispensed fibres towards the pre-determined direction and/or orientation. The further extensions may be in any suitable form. For example, the further extensions may comprise at least two arms. The further extensions may be flexible. In particular, the extensions may comprise at least two arms and the arms may be flexed and/or adjusted to control the angle formed between two adjacent arms. Even more in particular, the further extensions comprise at least two arms and form an angle of < 180° between two adjacent arms.
According to another particular aspect, the hollow elongate device may comprise a telescoping assembly comprising at least two members, wherein the first member is co-operatively engaged with the second member.
A second aspect of the present invention provides a hollow elongate device arranged to be connected to an outlet of a portable electrospinning apparatus for dispensing electrospun fibres, the hollow elongate device being capable of directing the dispensed fibres towards a pre-determined direction and/or orientation. The fibres dispensed from the outlet of the portable electrospinning apparatus may be deposited onto a surface. In particular, the dispensed fibres may be directed towards a pre-determined direction and/or orientation towards the surface onto which the fibres are deposited. The present invention also provides a construct for grounding at least one surface, the construct arranged to be contacted with the at least one surface on which electrospun fibres are deposited, wherein the construct is flexible to substantially conform to the shape of the at least one surface. In particular, the construct may be for use with an electrospinning apparatus. Any suitable electrospinning apparatus may be used. In particular, the electrospinning apparatus may be as described above.
According to a particular aspect, the construct may comprise at least one conductive structure with a flexible connection. The conductive structure may be a metal structure. The structure may be at least one wire, rod, tube and/or pipe.
Brief description of the figures
Figure 1 : A side plan view of an electrospinning apparatus according to one embodiment of the present invention.
Figure 2: A hollow elongate device according to one embodiment of the present invention.
Figure 3: A hollow elongate device according to one embodiment of the present invention.
Figure 4: A schematic representation of an electrospinning apparatus according to one embodiment of the present invention.
Figure 5: A side plan view of an electrospinning apparatus according to one embodiment of the present invention.
Figure 6: A circuit diagram of the circuit in an electrospinning apparatus according to another embodiment of the present invention. "HV" refers to a high voltage generator and "FAN" refers to a fan to direct the fibres being expelled from the outlet of the electrospinning apparatus. Figure 7: A hollow elongate device according to a second embodiment of the present invention.
Detailed description of the invention
Bibliographic references mentioned in the present specification are for convenience listed in the form of a list of references and added at the end of the examples. The whole content of such bibliographic references is herein incorporated by reference.
Most existing electrospinning devices are of a standing arrangement and restricted to laboratory or industrial usage. The problem with this arrangement is that it is non-portable and cannot be moved from one place to another easily. Accordingly, the advantage of a portable electrospinning device is that it can be easily moved from one place to another so that the device may be used for various applications. For example, the portable electrospinning device according to the present invention may be used in households by individuals as well as in small-scale industries and research.
Accordingly, a first aspect of the present invention is a portable electrospinning apparatus for generating fibres. The apparatus comprises:
- at least one reservoir for holding at least one electrospinning medium;
- an outlet for dispensing the electrospun fibres;
- a grounded electrode for contacting a surface onto which the fibres are deposited; and
- a hollow elongate device adapted to connect to the outlet, the hollow elongate device being capable of directing the dispensed fibres towards a pre-determined direction. For the purposes of the present invention, portable electrospinning apparatus is defined as an apparatus used for electrospinning which can be easily carried and moved or transported from one place to another. For example, the portable electrospinning apparatus according to the present application may be a hand- held electrospinning apparatus such that the apparatus is small and/or light enough to be operated while being held in a user's hands.
The hollow elongate device may be adapted to connect to the outlet of the electrospinning apparatus by any suitable connection. For example, the hollow elongate device may be connected to the outlet by frictional contact between the hollow elongate device and the outlet. Alternatively, the outlet may comprise connection means to allow the hollow elongate device to connect to the outlet of the electrospinning apparatus. For example, the connection means may comprise an O-ring at an interface between the outlet and the hollow elongate member. The connection means may also comprise a locking mechanism between the outlet and the hollow elongate member. The locking mechanism may comprise any one or a combination of a press-fit, interference fit or spring loaded mechanism. The connection means may also comprise an adhesive for adhering the hollow elongate device to the outlet of the electrospinning apparatus. The adhesive may be a layer of glue or any other suitable means of adhering two surfaces together.
According to a particular aspect, the hollow elongate member may be connected to the outlet of the electrospinning apparatus permanently or may be releasably removable from the outlet of the electrospinning apparatus.
At least a part of the hollow elongate member may be made of at least one dielectric material. For example, the dielectric material may be selected from the group consisting of: ceramics, refractory materials such as metal oxides, oil- impregnated paper, pressboard, mica, elastomers, press-moulded resins, polyethylene, polypropylene, polystyrene, polytetrafluoroethylene, polyvinyl chloride, polymethyl methacrylate, polyamide, polyimide, porcelain, polysilicates, polyalkenes, polyxylenes, silicones, polytetrafluoroethylene and mixtures thereof. The polysilicates may be in the form of mica sheets or slices. The dielectric material may protect a user of the electrospinning apparatus from high voltage and focus the deposition of the electrospun fibre by expulsion from the outlet of the electrospinning apparatus to the surface onto which the fibres are deposited.
The hollow elongate device has an inner surface and an outer surface. According to a particular aspect, at least a part of the inner surface of the hollow elongate device may be coated and/or layered with at least one adsorbent material. The layering of the inner surface may be in the form of a padding of at least one adsorbent material on the inner surface. The adsorbent material may adsorb the evaporating solvent expelled from the outlet of the electrospinning apparatus during the electrospinning process. In this way, the user is protected from the evaporating solvent, especially when the solvent may be considered to be toxic or hazardous to the user. Solvent exposure to the user is also reduced. Any suitable adsorbent material may be used. For example, the adsorbent material may be selected from the group consisting of: laminated charcoal, silica gel, dessicants, synthetic resins, naturally occurring resins, and mixtures thereof. The dessicants may be calcium chloride or calcium sulphate.
The hollow elongate device may be of any suitable shape and size. For example, the hollow elongate device may comprise a first end and a second end, the first end being adapted to connect to the outlet of the electrospinning apparatus. According to a particular aspect, the hollow elongate device may be conical shaped. In particular, the diameter of the hollow elongate device may increase from the first end to the second end. The hollow elongate device may keep away the turbulence and maintain an electrospinning jet during the electrospinning process. According to another particular aspect, the hollow elongate device may comprise further extensions capable of further directing the dispensed fibres towards the pre-determined direction and/or orientation. The further extensions may be flexible. The further extensions may be in the form of at least two arms. In particular, the angle between two adjacent arms may be adjusted to < 180°. The angle between two adjacent arms may be adjusted according to the area of the surface onto which the electrospun fibres are deposited. For example, if it is desired to coat only a part of a surface of a substrate, the angle between two adjacent arms of the hollow elongate device may be adjusted such that the electrospun fibres are directed towards that part of the surface of the substrate. In particular, if a wider area of the surface of the substrate is to be coated with the deposited electrospun fibres, the two adjacent arms may be adjusted to form a larger angle. In contrast, if a smaller area of the surface of the substrate is to be coated with the deposited electrospun fibres, the two adjacent arms may be adjusted to form a smaller angle.
Figure 1 shows an electrospinning apparatus 100. Electrospinning apparatus 100 has an outlet 101 from which electrospun fibres 106 are dispensed onto a grounded substrate surface 104. A hollow elongate device 102 is connected to outlet 101 of electrospinning apparatus 100. In particular, hollow elongate device 102 may be in the form of a cone.
An alternate hollow elongate device is shown in Figure 2. In particular, Figure 2 shows a hollow elongate device connected to an outlet 201 of an electrospinning apparatus (not shown) having two extensions, 202a and 202b. Extensions 202a and 202b, which are flexible, can be adjusted in the direction indicated by the arrows in Figure 2. Accordingly, the angle α between extensions 202a and 202b can be adjusted depending on the area of the surface which is to be coated by the deposited electrospun fibres, as explained above. The hollow elongate device may also comprise a telescoping assembly comprising at least two members, wherein the first member is co-operatively engaged with the second member. For the purposes of this invention, a telescoping assembly refers to members that fit together like a set of cylinders that slide into one another, allowing extension and shortening of the assembly. The telescoping assembly may contain any number of members, with a minimum of two members and wherein the first member is co-operatively engaged with the second member. The number of members may vary depending on the length desired to extend the device to.
An example of such an arrangement is shown in Figure 3. Figure 3 shows a hollow elongate device 300 connected to an outlet 301 of an electrospinning apparatus (not shown). The hollow elongate device 300 comprises a telescoping assembly comprising three pairs of extensions members, 302a and 302b; 304a and 304b; and 306a and 306b. In particular, members 302a, 304a and 306a are all co-operatively engaged with the adjacent member. Similarly, 302b, 304b and 306b are all co-operatively engaged with the adjacent member. For example, member 302a is co-operatively engaged with member 304a, which is in turn co-operatively engaged with member 306a.
According to a particular aspect, the at least one reservoir may be for holding at least one electrospinning medium. The reservoir may be a container. The container may be replaceable. The medium may be any medium suitable for electrospinning. For example, the electrospinning medium may be a solution comprising at least one polymer. Any suitable polymer may be used for the purposes of the present invention. The polymer may be a hydrophilic polymer, a hydrophilic polymer and/or an amphiphilic polymer. For example, the polymer may be selected from the group consisting of: polyamide, polyester, polyacrylate, polysulfone and fluoropolymers. In particular, the polymer may be selected from the group consisting of: polycaprolactone, polyamides, polyimides, polycarbamides, polyolefins, polyurethanes, polyethylene oxide, polylactide, poly-L-lactic acid, polygyycolide, poly(glycolic acid), polyesters, poly(vinylidene fluoride), poly(vinylidene fluoride-co-hexafluoropropylene), poly(DL-lactide), poly(L-lactide), polydioxanone, chitin, collagen either in its native form or cross-linked, silk, chitosan, poly(glutamic-co-leucine), poly-lactic- glycolide acid, poly(L-lactic acid-caprolactone), polyacrylonitrile, poly(acrylonitrile-co-methacrylate), polymethylmethacrylate, polyvinylchloride, poly(vinylidenechloride-co-acrylate), polyethylene, polypropylene, nylon, aramid, polybenzimidazole, polyvinyl alcohol), cellulose, cellulose acetate, cellulose acetate butylate, polyvinyl pyrrolidone-vinyl acetates, poly(bis-(2- methoxy-ethoxyethoxy))phosphazene (MEEP), poly(ethyleneimide), poly(ethylene succinate), poly(ethylene sulphide), poly(oxymethylene-oligo- oxyethylene), poly(propyleneoxide), poly(vinylacetate), polyaniline, poly (ethylene terephthalate) , poly(hydroxy butyrate), SBS copolymer, poly(lactic acid), mixtures, copolymer and blends, copolymers and terpolymers thereof.
The electrospinning medium may also comprise at least one solvent for dissolving the polymer. Any suitable solvent may be used. For example, the solvent may be an organic or an inorganic solvent. The solvent may be selected according to the polymer used. Examples of suitable solvents which can be used in combination with different polymers are provided in Cheng-Ming Huang et al, Composites Science and Technology, 63:2223-2253, 2003. The solvent may be an aqueous based solvent. In particular, the solvent may be acetic acid. Even more in particular, when the polymer is poly(ethylene oxide) or polyvinyl alcohol), the solvent may be water; when the polymer is collagen, the solvent may be hydrochloric acid; when the polymer is cellulose acetate, the solvent may be acetic acid; and when the polymer is polyvinyl pyrrolidone), the solvent may be ethanol and/or acetic acid.
According to another particular aspect, the power supply for powering the apparatus may be any suitable power supply. For example, the power supply may be a high voltage supply. In particular, the power supply may be a low DC high voltage power supply. The power may be supplied by at least one battery. The battery may be at least one AA battery.
The outlet of the electrospinning apparatus may in any suitable form. For example, the outlet of the electrospinning apparatus may be a spinneret with a needle. In particular, the needle may be a metallic needle. The outlet of the electrospinning apparatus may be connected to the power supply of the electrospinning apparatus.
The electrospinning apparatus according to the present invention may further comprise at least one pump. Any suitable pump may be used for the purposes of the present invention. For example, the pump may be a battery-powered pump, a manually pressured pump or a motorized fluidic pump. In particular, the pump may be a syringe pump. The pump may be used for pumping electrospinning medium from the reservoir to the outlet of the electrospinning apparatus. In particular, when the electrospinning process is started, the pump pumps the electrospinning medium from the reservoir to the needle tip of the outlet of the electrospinning apparatus, forming a droplet at the tip.
The electrospinning apparatus also comprises a grounded electrode. The grounded electrode is suitable for contacting a surface onto which the electrospun fibres are deposited. The surface onto which the electrospun fibres are deposited are grounded so that a potential difference is formed between the outlet of the electrospinning apparatus and the surface. According to a particular aspect, the grounded electrode may be flexible to substantially conform to the shape of the at least one surface onto which the electrospun fibres are deposited. The shape of the grounded electrode may be adjusted to substantially conform to the shape of the surface onto which the electrospun fibres are to be deposited to adjust the local electric, magnetic, fluidic and temperature field near the grounded surface so that a more efficient coating is achieved over the entire grounded surface. A more targeted deposition of the electrospun fibres may also be achieved when the entire surface is grounded by the electrode. In this way, non-metallic surfaces may be completely grounded since the grounded electrode can be conformed into the shape of the surface. In particular, the grounded electrode may comprise at least one conductive structure with a flexible connection. The conductive structure may be a metal structure. The structure may be at least one wire, rod, tube and/or pipe.
A schematic representation of the arrangement of the electrospinning apparatus according to one embodiment of the present invention is shown in Figure 4. Figure 4 shows an electrospinning apparatus 400 powered by power supply 402. Power supply 402 may consist of AA batteries. Electrospinning apparatus 400 may comprise a reservoir 404 for holding polymer solution 406 which is used as the electrospinning medium. Polymer solution 406 may be pumped from reservoir 404 to outlet 410 of electrospinning apparatus 400 by any suitable means. For example, polymer solution 406 is pumped from reservoir 404 to outlet 410 by pump 408. Pump 408 may be battery-powered or manually pressured. A hollow elongate device 412 as described above may be connected to outlet 410. A grounded electrode 414 may also be connected to power supply 402. Grounded electrode 414 is placed on the surface of a substrate (not shown) which is to be coated by electrospun fibres formed from electrospinning apparatus 400. Electrospinning apparatus 400 may comprise a housing 416 which encloses power supply 402, reservoir 404 and pump 408.
Figure 5 shows a side plan view of one embodiment of an electrospinning apparatus of the present invention. Figure 5 shows an electrospinning apparatus 500 comprising a housing 502 which comprises reservoir 504 holding the electrospinning medium, a power supply (not shown) and pump (not shown). There is also provided a power button 516 which upon user intervention completes the power circuit within apparatus 500 and starts the electrospinning process. Electrospinning apparatus 500 also comprises an outlet 506 from which the electrospun fibres are dispensed. A hollow elongate device 508 is connected to outlet 506. Electrospun fibres 514 are dispensed from outlet 506 onto substrate surface 512 which is grounded by ground electrode 510.
Electrospinning uses an electrical charge to form a mat of fine fibres. Electrospinning shares characteristics of both the commercial electro-spray technique and the commercial spinning of fibres. The standard setup for electrospinning consists of a spinneret with a metallic needle, a syringe pump, a high-voltage power supply, and a grounded collector. A polymer, sol-gel, composite solution (or melt) is loaded into the syringe and this liquid is driven to the needle tip by a syringe pump, forming a droplet at the tip. When a voltage is applied to the needle, the droplet is first stretched into a structure called the Taylor cone. If the viscosity of the material is sufficiently high, varicose breakup does not occur (if it does, droplets are electro-sprayed) and an electrified liquid jet is formed. The jet is then elongated and whipped continuously by electrostatic repulsion until it is deposited on the grounded collector. Whipping due to a bending instability in the electrified jet and concomitant evaporation of solvent (and, in some cases reaction of the materials in the jet with the environment) allow this jet to be stretched to micro/nano meter-scale diameters. The elongation by bending instability results in the fabrication of uniform fibres with micro/nano meter-scale diameters.
The electrospinning process will be described with reference to Figure 5. The reservoir 504 may be connected to a pump (not shown) which pumps electrospinning medium from the reservoir 504 towards outlet 506 of electrospinning apparatus 500. Outlet 506 may consist of a single spinneret, multiple spinnerets, co-axial spinneret, bi-capillary spinneret, multi-capillary spinneret. The spinneret of outlet 506 is used to deliver a constant supply of the at least one electrospinning medium. A high voltage from a power supply (not shown) is applied to the at least one electrospinning medium at the spinneret of outlet 506. At a critical voltage, a jet of solution 514 of the medium is ejected from the tip of the spinneret of outlet 506 through hollow elongate device 508 and accelerate towards a surface 512 of a substrate. The surface 512 onto which the electrospinning jet 514 is collected may be grounded by a ground electrode 510 so that the electrospinning jet 514 is more readily deposited on surface 512. The solvent from the electrospinning jet 514 collected may evaporate upon cooling, or extracted by a suitable non-solvent on the surface 512, thereby forming fibres.
In particular, the electrospinning medium is extruded from reservoir 504, for example using a pump, or under the action of gravity, through a minute capillary aperture. Once the droplet meniscus of the extruded electrospinning medium forms, a process of solvent evaporation or cooling or extraction starts, which is accompanied by the creation of capsules with a semi-rigid envelope or crust, otherwise known as the Taylor cone. An electric field is generated by the potential difference between the extruder and precipitation surface 512. Because the electrospinning medium possesses a certain degree of electrical conductivity, the capsules become charged. Electric forces of repulsion between the molecular chains within the capsules lead to a drastic increase in hydrostatic pressure. The semi-rigid envelopes are stretched, and a number of point micro-ruptures are formed on the surface of each envelope leading to spraying of ultra-thin jets 514 of liquefied polymer from outlet 506. Under the effect of a Coulomb force, the jets 514 depart from the outlet 506 and travel towards the opposite precipitation surface 512, which is always grounded by ground electrode 510. Moving with high velocity in the space between the extruder and precipitation surface 512, the jet 514 cools or solvent therein evaporates, or extracted by any suitable non-solvent on the precipitation surface 512, thus forming fibres which are collected on the precipitation surface 512.
The flow-rate of the electrospinning medium may vary from 0.1 ml_/hour to 10 mL/hour. The reservoir of the electrospinning apparatus according to the present invention may be exchangeable so that a reservoir containing another electrospinning medium may be used. In this way, it is convenient to switch from one kind of electrospinning medium to another to meet different applications. The reservoir may also be disposable.
The outlet of the electrospinning apparatus may be connected to the power supply at either the positive or negative electrode of the power supply. When the power supply is switched on and the electrospinning apparatus is working, the polymer micro/nano fibre will be drawn from the outlet and preferable deposited towards the direction of grounded electrode by electric field force. In particular, the polymer micro/nano fibre may be drawn from the outlet and through a hollow elongate device which is connected to the outlet. The grounded electrode may be contacted with the coating target which can be any substantial item. The grounded electrode may comprise several conductive structures with a flexible connection. The conductive structure may be a metal structure. The structure may be at least one wire, rod, tube and/or pipe. In this way, the grounded electrode may be easily adjusted to fit the proper size and shape of the target.
Before the electrospinning process is started, the grounded electrode of the electrospinning apparatus is adjusted to fit the shape of the coating target and is subsequently attached to the target. A reservoir with the desired electrospinning medium is provided to the electrospinning apparatus. Upon user intervention of a button or switch on the electrospinning apparatus, the circuit within the electrospinning apparatus is completed, which triggers the pump to start and high voltage supply to generate polymer nano/micro fibres by forming the fibre jets which are dispensed through the outlet of the electrospinning apparatus. A hollow elongate device may be connected to the outlet from which the fibre jets are dispensed. The hollow elongate device may be as described above. In particular, the hollow elongate device is adjusted to get a desired coating profile as described above. The electrospinning apparatus may further comprise a fan or a blower to generate airflow substantially directed towards the outlet of the electrospinning apparatus. A circuit diagram of the electrospinning apparatus is shown in Figure 6. The electrospinning apparatus may also comprise a dehumidifier to improve the electrospinning environment.
The electrospinning apparatus may further comprise a combination of needle and cartridge as shown in Figure 7. In particular, Figure 7 shows an electrospinning apparatus 700 comprising needle 702 and cartridge unit 704. Cartridge unit 704 comprises a needle 706, a syringe 708 which holds electrospinning medium 710. Needle 706 is of a suitable size such that needle 706 can be inserted into needle 702. Needle 706 may be fully or partially inserted into needle 701. As shown in Figure 7, the cartridge unit 704 is inserted into the needle 701 from the front. The base of the cartridge unit 704 may be metallic to be used for electrospinning. Voltage supply 714 is connected to needle 701. The voltage supply 714 may be high voltage supply. A pump 712 is then used to inject the electrospinning medium 710 into needle 702. Alternatively, a force may be applied on syringe 708. Once the electrospinning process is completed, the cartridge unit 704 may be removed and replaced with another cartridge unit. In this way, different electrospinning medium may be easily loaded into the electrospinning apparatus 700. Cartridge unit 704 may be disposable or reusable.
The electrospinning apparatus according to any aspect of the present invention may be an electrospinning apparatus used for generating a fibrous network or fibrous structure from an electrospinning medium. The electrospinning medium may be a polymer solution. The fibrous structure may be in the form of a coating. The coating may be used for painting, as a water repelling coating, an insulation coating, a coating to inhibit growth of microorganisms, wound healing, wound dressing, tissue regeneration and other suitable applications in which a coating or spray device is used. The fibrous structures may also be used for solid, liquid and/or gas filtration applications,
The electrospinning apparatus according to the present invention may be in the shape of a gun. The electrospinning apparatus may be suitable for household applications or small-scale industrial use.
Another aspect of the present invention is a hollow elongate device arranged to be connected to an outlet of an electrospinning apparatus for dispensing electrospun fibres, the hollow elongate device being capable of directing the dispensed fibres towards a pre-determined direction and/or orientation.
The hollow elongate device may be connected to the outlet of any electrospinning apparatus. In particular, the electrospinning apparatus may be a portable electrospinning apparatus. Even more in particular, the electrospinning apparatus may be the electrospinning apparatus as described above.
The hollow elongate device may be adapted to connect to an outlet of an electrospinning apparatus by any suitable connection. For example, the hollow elongate device may be connected to the outlet by frictional contact between the hollow elongate device and the outlet. Alternatively, the outlet may comprise connection means to allow the hollow elongate device to connect to the outlet of the electrospinning apparatus. For example, the connection means may comprise an O-ring at an interface between the outlet and the hollow elongate member. The connection means may also comprise a locking mechanism between the outlet and the hollow elongate member. The locking mechanism may comprise any one or a combination of a press-fit, interference fit or spring loaded mechanism. The connection means may also comprise an adhesive for adhering the hollow elongate device to the outlet of the electrospinning apparatus. The adhesive may be a layer of glue or any other suitable means of adhering two surfaces together. According to a particular aspect, the hollow elongate member may be connected to the outlet of the electrospinning apparatus permanently or may be releasably removable from the outlet of the electrospinning apparatus.
At least a part of the hollow elongate member may be made of at least one dielectric material. For example, the dielectric material may be selected from the group consisting of: ceramics, refractory materials such as metal oxides, oil- impergnated paper, pressboard, mica, elastomers, press-moulded resins, polyethylene, polypropylene, polystyrene, polytetrafluoroethylene, polyvinyl chloride, polymethyl methacrylate, polyamide, polyimide, porcelain, polysilicates, polyalkenes, polyxylenes, silicones, polytetrafluoroethylene and mixtures thereof. The polysilicates may be in the form of form of mica sheets or slices. The dielectric material may protect a user of the electrospinning apparatus from high voltage and focus the deposition of the electrospun fibre by expulsion from the outlet of the electrospinning apparatus to the surface onto which the fibres are deposited.
The hollow elongate device has an inner surface and an outer surface. According to a particular aspect, at least a part of the inner surface of the hollow elongate device may be coated and/or layered with at least one adsorbent material. The layering of the inner surface may be in the form of a padding of at least one adsorbent material on the inner surface. The adsorbent material may adsorb the evaporating solvent expelled from the outlet of the electrospinning apparatus during the electrospinning process. In this way, the user is protected from the evaporating solvent, especially when the solvent may be considered to be toxic or hazardous to the user. Any suitable adsorbent material may be used. For example, the adsorbent material may be selected from the group consisting of: laminated charcoal, silica gel, dessicants, synthetic resins, naturally occurring resins, and mixtures thereof. The dessicants may be calcium chloride or calcium sulphate. The hollow elongate device according to the present invention may be of any suitable shape and size. For example, the hollow elongate device may comprise a first end and a second end, the first end being adapted to connect to the outlet of the electrospinning apparatus. The hollow elongate device may be 5-20 cm in length and/or 2-25 cm in diameter. According to a particular aspect, the hollow elongate device may be conical shaped. In particular, the diameter of the hollow elongate device may increase from the first end to the second end. The hollow elongate device may keep away the turbulence and maintain an electrospinning jet during the electrospinning process. The hollow elongate device may be useful for blocking out strong winds and high humidity from the fibres which are dispensed from the outlet of the electrospinning apparatus.
According to another particular aspect, the hollow elongate device may comprise further extensions capable of further directing fibres dispensed from an outlet of an electrospinning apparatus towards the pre-determined direction. The further extensions may be flexible. The further extensions may be in the form of at least two arms. In particular, the angle between two adjacent arms may be adjusted to < 180°. The angle between two adjacent arms may be adjusted according to the area of the surface onto which the electrospun fibres are deposited. For example, if it is desired to coat only a part of a surface of a substrate, the angle between two adjacent arms of the hollow elongate device may be adjusted such that the electrospun fibres are directed towards that part of the surface of the substrate. In particular, if a wider area of the surface of the substrate is to be coated with the deposited electrospun fibres, the two adjacent arms may be adjusted to form a larger angle. In contrast, if a smaller area of the surface of the substrate is to be coated with the deposited electrospun fibres, the two adjacent arms may be adjusted to form a smaller angle.
Figure 1 shows a hollow elongate device 102 connected to an outlet 101 of an electrospinning apparatus 100. Electrospun fibres 106 are dispensed from the outlet 101 onto a grounded substrate surface 104. In particular, hollow elongate device 102 is in the form of a cone.
An alternate hollow elongate device is shown in Figure 2. In particular, Figure 2 shows a hollow elongate device connected to an outlet 201 of an electrospinning apparatus (not shown) having two extensions, 202a and 202b.
Extensions 202a and 202b, which are flexible, can be adjusted in the direction indicated by the arrows in Figure 2. Accordingly, the angle α between extensions 202a and 202b can be adjusted depending on the area of the surface which is to be coated by the deposited electrospun fibres, as explained above.
The hollow elongate device may also comprise a telescoping assembly comprising at least two members, wherein the first member is co-operatively engaged with the second member. For the purposes of this invention, a telescoping assembly refers to members that fit together like a set of cylinders that slide into one another, allowing extension and shortening of the assembly. The telescoping assembly may contain any number of members, with a minimum of two members and wherein the first member is co-operatively engaged with the second member. The number of members may vary depending on the length desired to extend the device to.
An example of such an arrangement is shown in Figure 3. Figure 3 shows a hollow elongate device 300 connected to an outlet 301 of an electrospinning apparatus (not shown). The hollow elongate device 300 comprises a telescoping assembly comprising three pairs of extensions members, 302a and 302b; 304a and 304b; and 306a and 306b. In particular, members 302a, 304a and 306a are all co-operatively engaged with the adjacent member. Similarly, 302b, 304b and 306b are all co-operatively engaged with the adjacent member. For example, member 302a is co-operatively engaged with member 304a, which is in turn co-operatively engaged with member 306a. Another aspect of the present invention is a construct for grounding at least one surface on which electrospun fibres are deposited, wherein the construct is flexible to substantially conform to the shape of the at least one surface.
The construct may be for use with an electrospinning apparatus. In particular, the electrospinning apparatus may be a portable electrospinning apparatus. Even more in particular, the electrospinning apparatus may be the electrospinning apparatus as described above. The construct may be a grounded electrode.
According to a particular aspect, the construct may be suitable for contacting a surface onto which fibres dispensed from an electrospinning apparatus are deposited. The surface onto which the electrospun fibres are deposited are grounded so that a potential difference is formed between an outlet of the electrospinning apparatus from which fibres are dispensed and the surface.
The construct may be flexible to substantially conform to the shape of the at least one surface onto which electrospun fibres are deposited. The shape of the construct may be adjusted to substantially conform to the shape of the surface onto which the electrospun fibres are to be deposited to adjust the local electric, magnetic, fluidic and temperature field near the grounded surface so that a more efficient coating is achieved over the entire grounded surface. A more targeted deposition of the electrospun fibres may also be achieved when the entire surface is grounded by the construct. In this way, non-metallic surfaces may be completely grounded since the construct can be conformed into the shape of the surface. In particular, the construct may comprise at least one conductive structure with a flexible connection. The conductive structure may be a metal structure. The structure may be at least one wire, rod, tube and/or pipe.
The construct may be contacted with the coating target which can be any substantial item. The construct may comprise several conductive structures with a flexible connection. The conductive structure may be a metal structure which could be easily adjusted to fit the proper size and shape of the target. The structure may be at least one wire, rod, tube and/or pipe. The temperature of the construct is also maintained by the conductive structures.
The construct may be made of any suitable material. For example, the material may be selected from the group consisting of: metal, semiconductor, ceramic, and mixtures thereof. The material of the construct may be the same as or similar to the material from which the hollow elongate device is made.
Although the present invention may have been described with particular reference to the accompanying figures, many variations are possible, as will be clear to the skilled reader, without departing from the spirit and scope of the invention.

Claims

Claims
1. A portable electrospinning apparatus for generating fibres, the apparatus comprising:
- at least one reservoir for holding at least one electrospinning medium;
- an outlet for dispensing the electrospun fibres;
- a grounded electrode for contacting a surface onto which the fibres are deposited; and
- a hollow elongate device adapted to connect to the outlet, the hollow elongate device being capable of directing the dispensed fibres towards a pre-determined direction.
2. The apparatus according to claim 1 , wherein at least a part of the hollow elongate device is made of at least one dielectric material.
3. The apparatus according to claim 2, wherein the dielectric material is selected from the group consisting of: ceramics, refractory materials, oil- impregnated paper, pressboard, mica, elastomers, press-moulded resins, polyethylene, polypropylene, polystyrene, polytetrafluoroethylene, polyvinyl chloride, polymethyl methacrylate, polyamide, polyimide, porcelain, polysilicates, polyalkenes, polyxylenes, silicones, polytetrafluoroethylene and mixtures thereof.
4. The apparatus according to any one of the preceding claims, wherein the hollow elongate device has an inner surface and an outer surface, and wherein the inner surface is coated and/or layered with at least one adsorbent material.
5. The apparatus according to claim 4, wherein the layering is in the form of a padding of the inner surface.
6. The apparatus according to claim 4 or claim 5, wherein the adsorbent material is selected from the group consisting of: laminated charcoal, silica gel, dessicants, synthetic resins, naturally occurring resins, and mixture thereof.
7. The apparatus according to any one of the preceding claims, wherein the hollow elongate device comprises a first end and a second end, the first end being adapted to connect to the outlet.
8. The apparatus according to any one of the preceding claims, wherein the hollow elongate device is conical shaped.
9. The apparatus according to claim 8, wherein the diameter of the hollow elongate device increases from the first end to the second end.
10. The apparatus according to any one of claims 1 to 7, wherein the hollow elongate device comprises further extensions capable of further directing the dispensed fibres towards the pre-determined direction.
11. The apparatus according to claim 10, wherein the further extensions are flexible.
12. The apparatus according to claim 10 or claim 11 , wherein the further extensions comprise at least two arms and form an angle of < 180° between two adjacent arms.
13. The apparatus according to any one of the preceding claims, wherein the hollow elongate device comprises a telescoping assembly comprising at least two members, wherein the first member is co-operatively engaged with the second member.
14. A hollow elongate device arranged to be connected to an outlet of a portable electrospinning apparatus for dispensing electrospun fibres, the hollow elongate device being capable of directing the dispensed fibres towards a pre-determined direction.
15. A construct for grounding at least one surface, the construct arranged to be contacted with the at least one surface on which electrospun fibres are deposited, wherein the construct is flexible to substantially conform to the shape of the at least one surface.
16. The construct according to claim 15, wherein the construct comprises at least one conductive structure with a flexible connection.
17. The construct according to claim 16, wherein the conductive structure is a metal structure.
18. The construct according to claim 16 or claim 17, wherein the condutive structure is a wire, rod, tube and/or pipe.
19. The construct according to any one of claims 15 to 18, wherein the construct is for use with an electrospinning apparatus.
PCT/SG2008/000444 2008-11-20 2008-11-20 A portable electrospinning apparatus WO2010059127A1 (en)

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WO2017059050A1 (en) * 2015-09-29 2017-04-06 Temple University-Of The Commonwealth System Of Higher Education Portable spinner and methods of use
CN107190336A (en) * 2017-07-24 2017-09-22 广东工业大学 A kind of electrospinning pen
US10639203B2 (en) 2014-11-11 2020-05-05 Nicast Ltd. Portable electrospinning device
WO2020243684A1 (en) 2019-05-30 2020-12-03 Skinner Jack L Device for polymer materials fabrication using gas flow and electrostatic fields
CN112673126A (en) * 2018-10-17 2021-04-16 花王株式会社 Electrostatic spinning device
CN113699688A (en) * 2021-10-15 2021-11-26 杭州俊为科技有限责任公司 Handheld nano film preparation equipment
CN115161882A (en) * 2022-07-14 2022-10-11 苏州凯姆勒绝缘材料有限公司 Low-dielectric polyimide/polytetrafluoroethylene microsphere composite nanofiber membrane and preparation method thereof
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Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10639203B2 (en) 2014-11-11 2020-05-05 Nicast Ltd. Portable electrospinning device
WO2017059050A1 (en) * 2015-09-29 2017-04-06 Temple University-Of The Commonwealth System Of Higher Education Portable spinner and methods of use
IL258429A (en) * 2015-09-29 2018-05-31 Univ Temple Portable spinner and methods of use
US12031252B2 (en) 2015-09-29 2024-07-09 Temple University-Of The Commonwealth System Of Higher Education Portable spinner and methods of use
CN107190336A (en) * 2017-07-24 2017-09-22 广东工业大学 A kind of electrospinning pen
CN112673126A (en) * 2018-10-17 2021-04-16 花王株式会社 Electrostatic spinning device
CN112673126B (en) * 2018-10-17 2023-09-01 花王株式会社 Electrostatic spinning device
WO2020243684A1 (en) 2019-05-30 2020-12-03 Skinner Jack L Device for polymer materials fabrication using gas flow and electrostatic fields
WO2023021070A1 (en) 2021-08-19 2023-02-23 Swansea University Fluid ionising device
CN113699688A (en) * 2021-10-15 2021-11-26 杭州俊为科技有限责任公司 Handheld nano film preparation equipment
CN115161882A (en) * 2022-07-14 2022-10-11 苏州凯姆勒绝缘材料有限公司 Low-dielectric polyimide/polytetrafluoroethylene microsphere composite nanofiber membrane and preparation method thereof
CN115161882B (en) * 2022-07-14 2024-02-27 苏州凯姆勒绝缘材料有限公司 Low-dielectric polyimide/polytetrafluoroethylene microsphere composite nanofiber membrane and preparation method thereof

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