(133b) Designer Stabilizer for Preparation of Pristine Graphene/Polysiloxane Films and Networks

A designer polysiloxane-based stabilizer for graphene was synthesized and applied to prepare a highly conductive polymer film. This stabilizer was simultaneously used as the polymer matrix. To synthesize the stabilizer, 1-ethynylpyrene was grafted to the backbone of a poly(dimethylsiloxane)-co-(methylhydrosiloxane) random copolymer by Pt-catalyzed hydrosilylation with a SiH: ethynyl ratio of 1.0:1.3. Dispersion of graphene in chloroform was prepared through the π-π interactions between the graphene sheets and the pyrene groups of the resulting copolymer. A graphene/polymer film was cast from this dispersion. SEM and TEM images confirmed the homogeneous distribution of the graphene sheets in the film.  The conductivity of this film with 4 wt% loading of graphene was measured to be 220 S/m.  This is the first case of a melt-processable, conductive graphene/polymer film reported in the literature. Later the ratio of SiH:ethynyl was changed to 1.7:1.0, which led to self-crosslinking of the polymer at 110 ⁰C and resulted in a direct production of a conductive graphene/silicon elastomeric composite. The crosslinking reaction was observed by FT-IR spectroscopy and the network formation was confirmed by swelling and extraction of the product.