Neutron reflectivity studies of thin diblock copolymer films

Abstract

We present a Neutron Reflection study of the behavior of thin films of symmetric poly(styrene-b-deuterium labeled methyl methacrylate diblock copolymers (P(S-b-D-MMA)) confined between two surfaces. The reflectivity of neutrons9 provides a novel means of investigating a wide range of polymer surface and interfacial phenomena with a spatial resolution less than a nanometer. The great potential of the technique is the spatial resolution with which features of the resulting morphology can be quantitatively addressed, e.g., the interfacial thickness. In this report we have shown that P(S-b-D-MMA) copolymers orient parallel to the surface of a film by annealing at temperatures above the glass transition. The interface between the copolymer microdomains can be described with a linear profile with width of 56 ± 2 Angstrom. We have also used neutron reflectometry to study the effect of the copolymer molecular weight on the ordering process and the interfacial thickness, as well as the effect of the isotopic substitution.