Synthesis, characterization and biocompatibility studies of oligosiloxane modified polythiophenes

This paper describes the preparation and characterization of homopolymers of 3-oligo(dimethylsiloxane)thiophene macromonomers, V–VIII, and copolymers with 3-methylthiophene. The thiophene macromonomers were prepared by hydrosilylation reaction between ω-(Si–H)-oligo(dimethylsiloxane), I–IV, and 3-propenylthiophene using a platinum-divinyltetramethyldisiloxane complex as the catalyst. The products were characterized by 1H, 13C, 29Si NMR and IR spectroscopy; DSC (differential scanning calorimetry) and GPC studies. Two distinct glass transition temperatures are observed for poly[VIII], a Tg at −79 °C corresponds to the soft oligo(dimethylsiloxane) phase and the Tg at 190 °C corresponds to the hard thiophene backbone. Homopolymers of V and VI, and copolymers may be doped with I2 to generate electronic conductive material, a copolymer of poly[V]-co-poly[3-methylthiophene] (50/50, w/w) has an electronic conductivity value of 5 × 10−5 S/cm at 25 °C. The polymers are tractable and may be molded into thin films; a number of the polymers are soluble in organic solvents. Polythiophene modified with oligosilioxanes are biocompatibile; the polymers minimally interfere with the growth of HeLa cells.