OPTICAL-PROPERTIES OF MICROCONFINED LIQUID-CRYSTALS

This paper is concerned with studies of birefringence and optical acti vity of the twisted nematic mixture 5CB/CB15 confined to cylindrical p ores of ANOPORE (AP) membranes. Both birefringence and optical activit y of the liquid crystal (LC) filled membranes exhibit unusual properti es. The sign of the optical activity is reversed with respect to the b ulk LC phase. Measurements have been performed using polarizing micros copy and generalized transmission ellipsometry. By means of C-13-NMR a nd FTIR experiments an increase of the tilt angle between local direct or and membrane normal with raising chiral dopant concentration could be proved. However, an unambiguous model for the structure of the chir al director field inside the pores could not be established up to now.