The structure of PEO–PPO–PEO triblock copolymers at the water/air interface

Abstract

Neutron reflectivity was employed to detect a layer of water-soluble PEO–PPO–PEO triblock copolymers adsorbed from D 2O. The thickness of the layer (estimated from single-layer fits) grows linearly with the chain length in agreement with the theory of the “simple brush”. The results are consistent with previous ellipsometric findings indicating the formation of a PEO brush at the water/air interface. The segment density profile is more diffuse than predicted by the simple brush model but the higher approximation (known as “parabolic brush”) does not describe our results adequately.