Fiber adhesive material
A fiber velvet comprising nano-size fibers or nanofibrils attached to micro-size fibers is disclosed. Methods of manufacturing the velvet as well as various uses of the velvet are also described. For example, the fiber velvet can be used as a thermal interface or as an adhesive material. The nanofibrils may be attached to a flat base or membrane, or may be attached to the tip portions of the micro-size or larger diameter fibers. Various attributes of the micro-size fibers and of the nano-size fibers, for example, geometry (e.g. size, length, packing density) material type (e.g. carbon, metal, polymer, or ceramic) and properties (e.g. conductivity, modulus, surface energy, dielectric constant, surface roughness) can be selected depending on the desired attributes of the fiber velvet. The nanofibrils have a diameter of less than about 1 micron, and may advantageously be formed from single walled and/or multi-walled carbon nanotubes.
1. An adhesive material for attaching to a mating surface, comprising:
a base;
an array of electroflocked first fibers bonded to the base, each having a cross sectional diameter of less than approximately 15 microns; and
an array of second fibers bonded predominantly to a distal portion of at least some of said first fibers and having a cross sectional diameters of less than about 1 micron, said second fibers being arranged and configured to form an intermolecular (e.g. van der Waals) bond when pressed against the mating surface.
2. The adhesive material of claim 1 , wherein the first fibers have a diameter of approximately 5 to 10 microns.
3. The adhesive material of claim 1 , wherein the second fibers have a diameter of approximately 0.005 to 0.5 microns.
4. The adhesive material of claim 1 , wherein the second fibers are substantially parallel to the first fibers.
5. The adhesive material of claim 1 , wherein the first fiber extends in a normal direction from the base.
6. The adhesive material of claim 1 , wherein the first fiber extends in a direction to form an oblique angle with the base.
7. The adhesive material of claim 6 , wherein the second fibers are substantially skew to the first fiber.
8. The adhesive material of claim 7 , wherein the second fibers are substantially parallel to a normal direction extending from the base.
9. The adhesive material of claim 1 , wherein the second fibers comprise carbon nanotubes.
10. The adhesive material of claim 1 , wherein the first fiber extends from at least one side of the base.
11. The adhesive material of claim 10 , wherein the first fiber extends from both sides of the base.
12. The adhesive material of claim 1 , further comprising a coating material located on tips of the second fibers and in contact with the first surface.
13. The adhesive material of claim 12 , wherein the coating material is a metal.
14. The adhesive material of claim 12 , wherein the coating material is a polymer.
15. The adhesive material of claim 1 , wherein the portion is the fiber tip area.
16. The adhesive material of claim 1 , wherein the first fiber and the second fibers both comprise carbon.
17. The adhesive material of claim 1 , wherein an adhesive force between the adhesive material and the mating surface is approximately equal to or greater than 0.26 psi.
18. The adhesive material of claim 1 , wherein an adhesive force between the adhesive material and the mating surface is approximately equal to or greater than 2.6 psi.
19. The adhesive material of claim 1 , wherein an adhesive force between the adhesive material and the mating surface is approximately equal to or greater than 26 psi.
20. The adhesive material of claim 1 , wherein an adhesive force between the adhesive material and the mating surface is approximately equal to or greater than 260 psi.
21. A fabricated microstructure, comprising:
a base;
a shaft with a length of about 500 microns and being connected to the base, said shaft having a diameter of between about 3 and 15 microns; and
an array of whiskers having terminal ends formed at an end of said shaft distal from said base, said array of whiskers having a width of less than about 10 microns.