Monolayers and multilayers of mesogen-substituted acetylene monomers and polymers.

摘要

With a view toward improving knowledge of the properties of organic molecules in monomolecular films, the general class of mesogen-substituted acetylene compounds was chosen for study. Such compounds potentially find application as both nonlinear optical and electrically-conducting materials. Monolayer properties were discovered through surface analytical methods, such as, Brewster angle microscopy, epifluorescence microscopy, in situ ultraviolet spectroscopy, and surface potentiometry.; The Langmuir-Blodgett-Kuhn (LBK) technique was used to study the monolayer properties of a series of substituted acetylene monomers. Preliminary work with substituted liquid crystalline monoacetylenes and phenylacetylenes pointed the way toward possible improvements in the molecular design. Subsequently, synthesis of a new phenylacetylene monomer, 4-(4{dollar}spprime{dollar}-ol-biphenyl-4-decanoxy)-phenylacetylene, with improved reactivity in thin solid films was achieved. In addition, a new substituted anthrylacetylene, 2-(10-(4{dollar}spprime{dollar}-ol-biphenyl-4-oxy) dodecanoxymethyl)-anthryl)-trimethylsilylacetylene, was synthesized.; LBK was also used to produce monomolecular films of phenylene acetylene rigid-rod polymers; poly(2-(11-hydroxyundecanoxy)-5-methoxyphenylene-ethynylene), poly(2-(11-hydroxyundecanoxy)-{dollar}5{dollar} -methoxyphenylene-ethynylene-pyridine-ethynylene), and poly(2,5-di(11-hydroxyundecanoxy)-phenylene-ethynylene-pyridinium bromide-ethynylene). At the air-water interface, two of the polymers were observed to form microscopic network morphologies after treatment by a simple processing procedure. The properties of one polymer's network was studied in detail, including the network dynamics. A model for the nanoscale orientation of the polymer within its network is proposed. A new method for estimating the line tension between 2D phases based on the observation of cell coalescence is presented.