Synthesis, electrical conductivity, and nonlinear optical property of poly (2-cyano-5-methoxy-1, 4-phenylenevinylene)

Abstract

Poly(2-cyano-5-methoxy-1, 4-phenylenevinylene), PCMPV, and a series of PPV copolymers containing 2-cyano-5-methoxy-1, 4-phenylenevimylene (CMPV) units were prepared via the water-soluble precursor method. They were obtained in film form and were doped with $FeCl_3$. Doping of undrawn and drawn film of PCMPV homopolymer with $FeCl_3$ led to conductivity of $9.1\times10^{-5}-7.2\times10^{-4}$ S/cm. Conductivity of $FeCl_3$ doped copolymer films ranged from $3.0\times10^{-4}$ - 4.1 S/cm depending on composition. The copolymer containing very low level ($\sim$ 5 mole %) of CMPV unit revealed the highest conductivity among the copolymer compositions. On the other hand precursor polymer films of PCMPV and 35PCMPV were cast from water solution onto tin-oxide coated glass, the nonlinear optical chromophores in the polymer films were aligned by corona discharge poling, and nonlinear optical properties were investigated. The resulting electro-optic coefficients of PCMPV and 35CMPV were $3.5\times10^{-8}$ e.s.u. (1.16 pm/V) and $3.0\times10^{-8}$ e.s.u.(1.06 pm/V), respectively.