Langmuir and Langmuir-Blodgett films of side chain liquid-crystalline poly(maleic acid-alt-1-alkene)s

Langmuir layers of side-chain Liquid-crystalline poly(maleic acid-alt-1-alk ene)s (SCLCPs) with biphenyl mesogens were studied on water subphases but m ere also transferred by the use of the Langmuir-Blodgett technique. Brewste r angle microscopy showed that the SCLCPs with methoxybiphenyl mesogens str ongly aggregate on the water subphase and form islands, which merge upon co mpression. In contrast, SCLCPs with cyanobiphenyl mesogens spread nicely an d compression of these polymers resulted in the formation of triple layers. Langmuir monolayers of SCLCPs with methoxybiphenyl mesogens show Z-type tr ansfer. Atomic force microscopy and X-ray reflectivity measurements of the resulting Langmuir-Blodgett mono- and/or multilayers indicate that the side chains of these polymers are possibly tilted. The multilayers have a doubl e layer periodicity, which requires a reorientation of the side chains duri ng or after transfer. Annealing of these Langmuir-Blodgett films resulted i n an increase of the mean film thickness and a more uniform d spacing withi n the multilayer. With atomic force microscopy droplets were observed on to p of the multilayer, indicating dewetting of the upper layers.