Porous Substrates, Articles, Systems and Compositions Comprising Nanofibers and Methods of Their Use and Production
Porous and/or curved nanofiber bearing substrate materials are provided having enhanced surface area for a variety of applications including as electrical substrates, semipermeable membranes and barriers, structural lattices for tissue culturing and for composite materials, production of long unbranched nanofibers, and the like. A method of producing nanofibers is disclosed including providing a plurality of microparticles or nanoparticles such as carbon black particles having a catalyst material deposited thereon, and synthesizing a plurality of nanofibers from the catalyst material on the microparticles or nanoparticles. Compositions including carbon black particles having nanowires deposited thereon are further disclosed.
1 . A method of producing nanofibers, the method comprising:
providing a substrate comprising a plurality of microparticles, glass or quartz fibers, or nanoparticles, each having a catalyst material deposited thereon; and
synthesizing a plurality of nanofibers from the catalyst material on the microparticles, glass or quartz fibers, or nanoparticles.
2 . The method of claim 1 , wherein the nanofibers comprise nanowires.
3 . The method of claim 2 , wherein synthesizing the plurality of nanowires comprises:
depositing a gold colloid on at least a portion of the overall surface area of the substrate; and
growing the nanowires from the gold colloid with a VLS synthesis technique.
4 . The method of claim 1 , wherein the substrate comprises carbon black particles.
5 . The method of claim 1 , wherein the substrate comprises glass or quartz microspheres.
6 . The method of claim 1 , wherein the plurality of nanofibers comprises a semiconductor material selected from group IV, group II-VI and group III-V semiconductors.
7 . The method of claim 1 , wherein the plurality of nanofibers comprise silicon or silicon oxide.
8 . The method of claim 1 , further comprising removing the synthesized nanofibers from the surface of the substrate, following synthesis of the nanofibers, to produce a population of detached nanofibers.
9 . The method of claim 8 , wherein said removing comprises heating the substrate to remove the nanofibers.
10 . The method of claim 9 , wherein said heating comprises heating the substrate to a temperature greater than about 500 degrees Celsius.
11 . The method of claim 1 , wherein the substrate comprises carbon particles.
12 . The method of claim 1 , wherein the substrate is free of attachment to another solid support.
13 . The method of claim 1 , wherein the substrate comprises a powder.
14 . The method of claim 11 , wherein one or more surfaces of the carbon particles are curved.
15 . The method of claim 1 , wherein the substrate comprises microspheres, spherical glass or quartz fibers, or spherical nanoparticles.
16 . The method of claim 1 , wherein the substrate comprises glass fibers.
17 . The method of claim 1 , wherein the substrate comprises quartz fibers.
18 . The method of claim 1 , wherein the substrate comprises glass microfibers.
19 . The method of claim 1 , wherein the substrate comprises quartz microfibers.
20 . The method of claim 1 , wherein the substrate comprises fiberglass.
21 . The method of claim 1 , wherein the substrate comprises microspheres.