We investigated the interrelationships among the crystal structures and the physical/ferroelectric/piezoelectric/rheological properties of a thermoplastic composite based on poly(vinylidene fluoride) (PVDF)/carbon nano tube (CNT). The composite was prepared by solution blending and the composite films were formed by hot-pressing. The contents of CNT were from 0.001 wt% to 3 wt%. To induce piezoelectric beta-form crystal structure, the composite films were drawn by 400% elongation. The samples were poled at high voltage and high temperature for polarization of the film. The beta-forrn crystal increased with CNT contents, passing through a peak, and decreased. The structural changes depended on the CNT contents, drawing and poling conditions. The maximum amount of beta-crystal could be produced by optimum conditions in this study. The drawn and poled PVDF/CNT (0.2 wt%) composite film had the highest value of piezoelectricity. In the rheological properties, dynamic viscosity, the extent of shear thinning behaviors and relaxation time were increased with the CNT content. (C) Koninklijke Brill NV, Leiden, 2009