Fabrication of nanofibers as dry adhesives and applications of the same
A method of forming a dry adhesive by includes forming an electrospun non-woven of a spinnable polymer, wherein the polymer fiber forming the non-woven is aligned. A dry adhesive is provided that comprises aligned polymeric nanofibers. The polymeric nanofibers may be formed from a mixture of highly spinnable material is combined with an adhesive component to further enhance the adhesion onto substrates. The non-woven can further be processed by plastic deformation to create microprotrusions.
1. A method for producing a dry adhesive, the method comprising the steps of:
providing a spinnable material;
electrospinning the spinnable material to thereby form a non-woven dry adhesive, wherein the non-woven dry adhesive comprises polymeric nanofibers, where said polymeric nanofibers are substantially aligned in a parallel alignment.
2. The method of claim 1 , wherein the spinnable material is a solution of a polymeric material and a solvent.
3. The method of claim 2 , wherein the polymeric material is selected from the group consisting of polyurethanes, polycaprolactones, polyvinyl alcohols, poly(vinyldiene fluoride)s, polyamides, polybenzimidazoles, polycarbonates, polyacrylonitriles, polylactic acids, polyethylene oxides, polyethylene terephtalates, polystyrenes, polyvinyphenols, polyvinylchlorides, cellulose acetates, polyether imides, polyethylene glycols, poly(ferrocenyldimethylsilane)s and mixtures thereof.
4. The method of claim 2 , wherein the solvent is selected from the group consisting of toluene, tetrahydrofuran, dichloromethane, chloroform, methanol, dimethylacetamide, dimethyl sulfoxide, dimethylformamide, xylene, acetone, ethanol, formic acid, distilled water, trifluoracetic acid, hexafluoro-2-propanol and mixtures thereof.
5. The method of claim 2 , wherein the solution further includes an adhesive component, the adhesive component being a viscoelastic or a resin-curable component.
6. The method of claim 5 , wherein the adhesive component has a Young's modulus of 0.1 GPA or less.
7. The method of claim 6 , wherein the adhesive component is flowable at room temperature.
8. The method of claim 5 , wherein the adhesive component is selected from the group consisting of polyisobutylenes, pressure sensitive adhesive materials and tackifiers.
9. The method of claim 5 , wherein the adhesive component is selected from the group consisting of polyisobutylene, acrylics, butyl rubber, ethylene-vinyl acetate (EVA) with high vinyl acetate content, natural rubber, nitriles, silicone rubbers, styrene block copolymers (SBC), styrene-butadiene-styrene (SBS), styrene-ethylene/butylene-styrene (SEBS), styrene-ethylene/propylene (SEP), styrene-isoprene-styrene (SIS), vinyl ethers, and mixtures thereof.
10. The method of claim 5 , wherein the adhesive component is selected from the group consisting of rosins, rosin derivates, terpenes, modified terpenes, aliphatic, cycloaliphatic and aromatic resins (C5 aliphatic resins, C9 aromatic resins, and C5/C9 aliphatic/aromatic resins), hydrogenated hydrocarbon resins, terpene-phenol resins (TPR), and mixtures thereof.
11. The method of claim 1 , wherein the non-woven dry adhesive has a shear adhesion strength that is higher than the normal adhesion strength.
12. The method of claim 1 , wherein the method further comprises the step of subjecting the non-woven dry adhesive to plastic deformation by passing the non-woven dry adhesive through an equal channel angular extrusion vial.
13. The method of claim 1 , wherein, in the step of electrospinning, the spinnable material is electrospun onto a surface of a substrate to form the non-woven dry adhesive, and the direction of substantial alignment of the nanofibers is parallel with the surface of the substrate.
14. The method of claim 1 , further comprising the steps of adhering the non-woven dry adhesive to an adherend, and further securing the adherend to another surface, wherein the non-woven dry adhesive is reusable, thereby allowing the adherend to be removed from the another surface, wherein when the non-woven dry adhesive is securing the adherend to another surface the direction of substantial alignment of the nanofibers is parallel with the surface of the adherend and the surface of the another surface.
15. The method of claim 1 , wherein the non-woven dry adhesive includes millions of substantially aligned polymeric nanofibers.
16. A method for producing a dry adhesive, the method comprising the steps of:
electrospinning a spinnable material to thereby form a non-woven dry adhesive, wherein the non-woven dry adhesive comprises polymeric nanofibers, where said polymeric nanofibers are substantially aligned in a parallel alignment; the non-woven dry adhesive being capable of adhering to the surface of an adherend, the non-woven dry adhesive thereby being capable of securing the adherend to another surface; wherein when the non-woven dry adhesive is securing the adherend to another surface, the direction of substantial alignment of the nanofibers is parallel with the surface of the adherend and the surface of the another surface.