Functionalized single walled carbon nanotube containing amino acid based hydrogel: a hybrid nanomaterial

Abstract

Fmoc-protected amino acid based (Fmoc-Phe-OH) hydrogel has been developed in our laboratory previously (S. Roy and A. Banerjee, Soft Matter, 2011, 7, 5300–5308). This hydrogel has been used to incorporate and disperse functionalized single-walled carbon nanotube (f-SWCNT) within the gel phase to make a hybrid hydrogel at physiological pH and temperature and this is a convenient procedure to create a f-SWCNT based hybrid nanomaterial. The hybrid hydrogel has been characterized using different microscopic studies including transmission electron microscopic imaging (TEM) and atomic force microscopic imaging (AFM) and rheological studies. The AFM study demonstrates a nice 1D alignment of f-SWCNTs on the surface of the gel nanofibers. Functionalized SWCNT containing hybrid hydrogels are more thermally stable than the native gel. Rheological experiments show that the hybrid hydrogel is a more elastic material than the native hydrogel obtained from the Fmoc-Phe-OH. Moreover, G′ (storage modulus) of the native hydrogel has been increased about 16 times upon the inclusion of f-SWCNT into the gel matrix. Conductivity of the f-SWCNT containing hydrogel has been found to be 3.12 S cm⁻¹ and conductivity of the f-SWCNT has dropped after incorporation of f-SWCNT into the hydrogel system.