Preparation of plasma-polymerized benzonitrile derivatives and their femtosecond time-resolved optical Kerr effect

Two kinds of linear soluble conjugated polybenzonitrile derivatives, plasma-polymerized aminobenzonitrile (PPABN) and plasma-polymerized nitrobenzonitrile (PPNBN), were successfully prepared by radio frequency glow discharge techniques. The results of Fourier transform infrared (FT-IR) and UV-Visible absorption spectra revealed that extensively conjugated CN double bonds have been formed in the plasma-polymerized benzonitrile derivatives. The femtosecond time-resolved optical Kerr effect (OKE) was used to measure the third-order optical nonlinearity. For the first time, an ultrafast response and non-resonant OKE of both polybenzonitrile derivatives were observed. Furthermore, the effects of molecular weights of polymers and their molecular structures on nonlinear optical properties were also investigated.