From spider spinning to bubble electro-spinning and from the wool structure to carbon super-nanotubes

摘要

In the past decade, considerable effort has been invested in developing new methods for producing nano-fibres, continuous or discontinuous. Nanofibres and nanoporous microspheres have remarkably large surface-to-volume ratios, and this 'nano-effect'6 has been demonstrated to result in unusual strength, high surface energy, surface reactivity, and high thermal and electric conductivity;;these characteristics improve performance for many applications (for example, filtration7). Electrospinning is a process capable of producing polymer nanofibres and nanoporous microspheres,10 but its output is extremely low and the mechanical characteristics of the product are far inferior to spider-spun fibre, which is of extraordinarily high specific strength and toughness. Production of electrospun fibre also requires a very high voltage (from several to several tens of kilovolts). Spider silk is actually a assembly consisting of thousands of nanofibres (Fig. 1), and this distinctive structure explains its very high strength and toughness.