Structure, deposition properties, and function of polyisobutylmethacrylate (PIBM) Langmuir-Blodgett films

Abstract

A polyisobutylmethacrylate (PIBM) monomolecular film at an air/pure water interface was stable and was not so viscous in the area range greater than 19 Å 2/residue. The CPK molecular model of PIBM in a closely packed monomolecular film predicts a 10- to 11-Å film thickness and a hydrophobic nature for both sides of the film. These predictions are consistent with the experimental results. The ester orientation was investigated by IR spectroscopy. Vertical deposition properties of PIBM monomolecular film onto silicon substrates with various water contact angles (θ) were investigated. Vertical multilayer deposition was possible for a hydrophobic silicon substrate (θ = 100°), yielding a uniform Y-type LB film. An alternating hetero LB film of cadmium stearate bilayer and PIBM bilayer was subjected to low-angle X-ray diffraction analysis, in order to obtain the monomolecular film thickness of PIBM (11 Å). Cadmium stearate LB films are known to undergo crystallization over a long period of time (>100 days at 20°C) but it was found that covering the cadmium stearate LB film with a PIBM LB film effectively inhibited the crystallization.