We have implemented and modified the technique of particle coagulation spinning (PCS) [1] to fabricate "hair-like" permeable and electrically conductive carbon nanotube -polymer composite fibers. Carbon nanotube fibers (CNF) of tens microns width and tenths of cm length, consist of an interconnected network of polymer chains and SWNT. CNFs possess a hierarchical pore structure in the wide range of pore sizes from several nanometers to microns [2]. The transport pores of CNF appear due to folding of the prefiber ribbon in the process of its extraction from the rinsing bath as the result of competition between capillary and elastic forces. In this study, we first describe this mechanism of fiber formation, which determines the pore structure morphology of dry SWNT fibers. Then, we show that by varying the parameters, which control the process, it is possible to tailor the pore structure of SWNT fibers. We further describe the different fiber morphologies obtained by modifying the multi-step PCS process.

Owing to their hierarchical nanostructure, CNFs combine unique properties of porous nanostructured scaffolds, permeable microfluidic conduits, and high area supports for bioactive agents and biocatalysts. CNFs are of particular interest for cell biotechnology due to their ability to support the attachment and proliferation of mammalian cells, including neural cells.

References: [1] Vigolo B et al. Science 290 (5495): 1331-1334 (2000). [2] Neimark A V et al. Nano Letters, 3, 419-423 (2003)

Acknowledgement: This work is supported by NIH grant R21EB002889.