ORIGIN OF ORIENTATION PHENOMENA OBSERVED IN LAYERED LANGMUIR-BLODGETT STRUCTURES OF HAIRY-ROD POLYMERS

The main chain orientation of polymers of the hairy-rod type in layered assemblies obtained by the Langmuir-Blodgett (LB) process has been investigated. The alignment of the transferred molecules parallel to the dipping direction is determined by the geometric conditions of the monolayer flow on the water subphase. Orientation due to the force field at the meniscus is negligible. Experimental data obtained for poly(tetramethoxytetraoctoxyphthalocyaninato)siloxane (PcPS), poly(gamma-methyl L-glutamate)-co-(gamma-n-octadecyl L-glutamate) (PG), isopentylcellulose (i-PC), and n-butylcellulose (n-BC) are theoretically analyzed in terms of the rheology of a two-dimensional liquid. The order parameter describing the degree of orientation of the backbones with regard to the dipping direction can be improved by annealing. This process obeys the time-temperature superposition principle.