NANOFIBER TECHNOLOGY: Bridging the Gap between Nano and Macro World

摘要

Nanofiber technology is an important branch of the growing discipline of nanotechnology. Materials in nanofiber form not only lead to superior functions due to the nano-effect, but also provide a means to deliver functions to higher order structures. Electrospinning is an attractive process capable of producing polymeric fibers having diameters ranging over several orders of magnitude, from the micrometer range to the nanometer range. Under certain spinning conditions for some polymer solutions, continuous yarn containing nanofibers can be produced. This phenomenon opens the door to a practical means of connecting nanostructured materials to macroscopic structures. To illustrate the concept of hierarchical translation of the properties of nanomaterials to higher order structures, a mulltiscale modeling approach is introduced using carbon nanotube reinforced composite fibrillar assemblies as an example. Encouraged by the simplicity of the electrospinning process and early demonstration of unique properties of nanofibers, there is an explosion of research activities worldwide. It is envisioned that higher level of scientific understanding of nanofibrous materials and creative applications of nanofibrous structures will be realized in the coming decade. Through process modeling and engineering design for manufacturing, the issue of productivity will be addressed. It is envisioned that more environmental friendly processes such as melt electrospinning will be developed. Hybrid processes, such as combining melt blowing and electrospinning are promising means to increase productivity and expand the performance limit. Along with new ways to produce the nanofibers, scientists will also develop better ways to harvest and test the nanofibers. While the commercial value of electrospun nanofibers depends on the reproducibility and productivity, the true value of the current electrospinning activities is in it's capability to generate nanoscale fibers, thus providing a means to facilitate the assessment of the nanoscale effect for a wide range of materials.