The characterization of Langmuir-Blodgett films of a non-linear optical, side chain liquid crystalline polymer

Monolayer film formation has been observed for a liquid crystalline copolymer containing a second-order non-linear optical side chain. The films were characterized on the aqueous subphase by a pressure-area per monomer unit isotherm and successfully transferred onto a glass substrate by the horizontal lifting method. The transferred Langmuir-Blodgett monolayers were characterized by surface plasmon resonance, attenuated total reflection-IR (ATR-IR) and UV-visible spectroscopy. The surface plasmon resonance study revealed the Langmuir-Blodgett films transferred at 5 dyn cm^-1 to be uniform but not those at 10 and 15 dyn cm^-1. The theoretical fit of the surface plasmon results for the monolayer Langmuir-Blodgett films transferred at 5 dyn cm^-1 coupled with ellipsometric results on a solution-cast film yielded the values for the refractive index and the thickness of the monolayer. ATR-IR and UV-visible spectra show that the copolymer has similar conformations in the monolayer and bulk states.