Fullerene (C60) Containing Poly (N-isopropylacrylamide) Thermo-responsive Smart Hydrogels and their Swelling Behavior

Fullerene (C-60) containing cross-linked poly (N-isopropylacrylamide) hydro gels (CFPNP) were synthesized by the polymerization of N-isopropylacrylamide (NIPAM) in the presence of C-60 using benzoyl peroxide (BPO) as initiator and N,N'-methylenebisacrylamide (MBA) as crosslinker in an inert atmosphere of nitrogen at 70 degrees C for 24 hrs. The cross-linked polymers were characterized by FTIR and TGA analyses and they were studied for their swelling behavior. The onset of thermal degradation and char residue were observed to increase by the incorporation of fullerene in the cross-linked polymers. The swelling properties of cross-linked poly (N-isopropylacrylamide) hydro gels with and without fullerene were studied in distilled water. The equilibrium swelling ratio is lower for the fullerene containing hydrogels than that of the hydro gel without fullerene. It was also observed that equilibrium swelling ratio decreases with increasing temperature. Both fullerene containing hydro gels and also the hydro gel without fullerene exhibit thermo-responsive behavior. Incorporation of fullerene in the cross-linked poly (N-isopropylacrylamide) polymer slightly decreases the lower critical solution temperature (LCST) of hydro gels because of hydrophobic nature of fullerene.