A study of block copolymer adsorption kinetics via internal reflection interferometry
Abstract
We present a new experimental approach to investigate polymer adsorption onto dielectric surfaces. This technique, internal reflection interferometry, employs multiple total internal reflections through a prism to measure the average refractive index and thickness of adsorbed layers. The adsorption kinetics of poly(ethylene oxide)–polystyrene block copolymer from dilute solutions in cyclopentane at 23 °C onto sapphire is presented. The sapphire surface is saturated within 30 min, in contrast with homopolymer adsorption, and the copolymer is irreversibly adsorbed with respect to pure solvent. Micellization of block copolymers dramatically affects adsorption kinetics and the final amount adsorbed. We suggest some mechanisms explaining the adsorption behaviour.