A study of the physical properties of polymer monolayers spread at the air-water interface

Abstract

An account is given of the methods of anionic polymerisation and characterisation used to prepare polymer samples, and the experimental methods used to examine their interfacial properties, when spread as so-called Langmuir monolayers on water. Specifically, these, are surface pressure - concentration isotherm studies, neutron reflectometry, ellipsometry of polarised light, and surface quasi-elastic light scattering. Hydrogenous and deuterated analogues of three different groups of polymers have been synthesised. These are ;syndio, iso and atactic poly (methyl methaciylate) SYNDIO-, ISO-, and ATAPMMA; poly (ethylene oxide), PEO;0.85:0.15 diblock copolymers of poly(methyl methacrylate) with poly (4-vinyl pyridine), PMMA4VP.The latter materials have been quaternised with hydrogenous and deuterated ethyl bromide to create partially poly-electrolyte materials, PMMA4VPQ. Thermodynamic information obtained from surface pressure data regarding the interaction between polymer segments and the subphase in each case is related to structural and compositional changes in the film measured as a function of surface concentration by neutron reflectometry. The trends described are supported by ellipsometric data, and preliminary experiments into the investigation of PMMA surface monolayer visco-elastic properties are described.