Molecular orientation in laser-induced periodic microstructure on polyimide surface

The dichroism of the laser-induced periodic microstructure on a polyimide s urface was studied with polarized reflectance infrared spectroscopy. The ex perimental 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 dia mine moiety tend to orient in a direction perpendicular to the nanolines. T his result indicates that the polyimide molecule chains tend to orient in a direction perpendicular to the nanolines. (C) 2000 American Institute of P hysics. [S0003-6951(00)02910-7].