Production and characterization of liquid crystal/polyacrylonitrile nano-fibers by electrospinning method

Abstract

We present that high birefringent nematic liquid crystal, 4-n-pentyl-4'-cyanobiphenyl, was incorporated into the polyacrylonitrile precursor which has a strong polar cyano group so as to produce electrospun nano-fibers, as the first time. Optical textures of nano-fibers were taken by polarized optical microscopy with different angles to determine the orientation degree of liquid crystal molecules in the center of the fiber. The molecules of liquid crystal self-ordered within the core of the fiber. Variation in morphology of liquid crystal/polymer nano-fibers were examined by utilizing both scanning electron microscopy and polarized optical microscopy depending on liquid crystal concentration in precursor and application voltage during electrospinning. Morphology of nano-fibers was significantly affected by electrospinning parameters and liquid crystal/polymer ratio. To understand phase separation and thermal stability of nano-fibers, calorimetric and thermogravimetric analyses were performed.