FTIR-ATR STUDIES OF DRAWING AND POLING IN POLYMER BILAMINATE FILMS

A large increase in the remnant polarization of drawn and poled poly (vinylidene fluoride) (PVF2)/nylon 11 bilaminates compared with the individual films observed in other studies provides the motivation for the examination of dipole orientation in variously treated single and bilaminate films with FTIR-ATR spectroscopy. Four ATR spectra are collected from each surface using two sample orientations and two light polarizations for each incident light angle. The incident light angle is varied to obtain information about the change in structure with depth. Computer simulations of the experimental optics using anisotropic optical constants aides in the interpretation of experimental results. As the result of simple one-way drawing in PVF2 and nylon 11, anisotropy in dipole orientation is observed in the plane transverse to the draw direction. In both single and bilaminate films, the average direction of the amide plane in nylon 11 and the CF2 dipoles in PVF2 resides in the plane of the film, perpendicular to the subsequent poling field direction as a result of one-way drawing. The transverse plane orientation is depth dependent in nylon 11 in both single and bilaminate films and is attributed to a surface-induced effect. Poling fields of 1.6 MV/cm produce large differences between the surfaces of single films and the bilaminates. At the interior interface of the drawn and poled bilaminates, the PVF2 and nylon 11 dipoles important in polarization appear to be random. The structural implications of this as well as other observations from the spectra are interpreted in terms of the large remnant bulk polarization in the poled bilaminate. (c) 1994 John Wiley & Sons, Inc.