Electrical Applications of Biofibers

11.08.2015 Innovative Biofibers from Renewable Resources

Miscellaneous Applications of Biofibers from Renewable Resource

Biofiber • Renewable resource • Electrode • Fiber • Chitosan • Nanocomposite • Supercapacitor

Chitosan fibers prepared through the wet-spinning approach were cross-linked with glutaraldehyde and later modified using polyalanine and multiwalled carbon nanotubes for potential use as electrode material for electrical double-layer capacitors [14Dor]. SEM images in Fig. 74.1 show the chitosan fibers modified using polyalanine and with MWCNT. The addition of polyalanine and CNTs onto chitosan fibers resulted in a porous structure shown in Fig. 74.1b. The conductivity of the chitosan/polyalanine/MWCNT fibers was 5.34 x 10-2 S cm-1 compared to

7.2 x 10-2 S cm-1 for the chitosan/polyalanine fibers. The nanocomposite fibers had a specific capacitance of 14.5 F cm-2 at a current density of 10 mA cm-2 suggesting that the fibers would be suitable as electrode materials.

In another study, wet spun chitosan fibers were in situ polymerized with aniline to form a biofiber hydrogel that had enhanced chemical and electrochemical actuation in response to pH and electrical stimulus [08Ism]. The presence of aniline was responsible for the electrochemical properties of the fibers. Aniline was found to be aggregated on the surface of the fibers, and the amount of aniline was lower at the center of the fibers. The electrical conductivity of the fibers at room temperature was 2.8 x 10-2 S cm-1, but the strain ratio and response time during electrochemical actuation were dependent on the pH of the electrolyte. Similar approaches have been used to coat natural cellulose fibers with MnO2 and carbon nanotubes for potential use as substrates for supercapacitors [13Gui].