Polarized ATR Measurements of Uniaxially Drawn PET Film

Introduction

In the process of forming film by the melting method, uniaxial or biaxial drawing of the film is typically conducted to improve the film properties according to the intended application. The orientation of molecules in drawn film changes according to the direction(s) in which the film was drawn, and the molecules will assume a specific orientation. The orientation can be evaluated using the transmission method to obtain the dichroic ratio, an absorbance ratio of the spectra obtained by irradiating the sample with polarized light parallel to and perpendicular to the draw axis of the sample. In contrast to this method, in which evaluation can only be conducted two-dimensionally, polarized light measurement by the ATR method permits evaluation along the Z-axis (thickness direction), in addition to the X-axis and Y-axis. Here, we present an example of evaluation of uniaxially drawn polyethylene terephthalate (PET) film using the polarized ATR measurement technique.

March 18, 2013 GMT