Molecular orientation in laser-induced periodic microstructure on polyimide surface

The dichroism of the laser-induced periodic microstructure on a polyimide surface was studied with polarized reflectance infrared spectroscopy. The experimental results show that the polar C=O groups in the polyimide exhibit a greater tendency of orienting in the direction parallel to the microlines while the nonpolar C–C–C linkages between the two benzene rings in the diamine moiety tend to orient in a direction perpendicular to the nanolines. This result indicates that the polyimide molecule chains tend to orient in a direction perpendicular to the nanolines.