Orientation of pores in microporous polyethylene films as determined by polarized absorption spectroscopy

Abstract

Microporous polyethylene films with good mechanical properties can be produced on the basis of hard-elastic specimens by uniaxial deformation. The so called “guest-host” effect [1, 2] was explored to determine the order parameter of pores in a series of PE membranes so produced by polarized absorption spectroscopy using dichroic dyes dissolved in the nematic liquid crystal ZLI 1840 (LC) as indicator. The parameter of the orientation order SA of the pores along the draw direction was found to increase with increasing spin draw. A qualitative comparison of SA with the thermodynamic behavior of the dye + LC systems confined in the pores was made. The results obtained are related to the mechanism of porous structure formation.

Keywords:

• Polyethylene membranes
• Fluorescent dyes
• Orientation order
• Liquid crystals
• Polarized-light absorption spectroscopy