Surface functionalization of cellulose with poly(3-hexylthiophene) via novel oxidative polymerization

Surface functionalization of cellulose with poly(3-hexylthiophene) (P3HT) was conducted with FeCl₃ as an oxidant in three different solvents: acetonitrile, chloroform, and hexane. Of these three solvents, hexane best promoted the grafting P3HT to cellulose with a high grafting ratio and molecular weight. The maxima of the UV-vis absorption and fluorescent spectra, observed at around 500 and 600nm, respectively, represented the build-up of the conjugated chain length formed by the grafting of P3HT onto the cellulose surface. The HOMO level of cellulose as determined by photoemission yield spectroscopy decreased from 4.83 to 4.67eV after modification with P3HT. Grafting P3HT onto the surface of cellulose provided super-hydrophobic property with a lotus effect. The conductivity of cellulose also improved significantly, from 10^-9 to 10^-6S/cm when P3HT was present on the surface. The thermal stability and crystallinity of cellulose decreased slightly upon graft polymerization with P3HT.