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 S_A of the pores along the draw direction was found to increase with increasing spin draw. A qualitative comparison of S_A 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.