Scaling of Domain Spacing of Block Copolymers Dilated by High-Pressure Carbon Dioxide
Timothy P. Francis, B D. Vogt, M Wang, J J. Watkins
The dependence of the interdomain spacing, d, of a phase separated poly(styrene-b-dimethyl siloxane) in high-pressure carbon dioxide is studied and shown to follow a new power law scaling, , where ? is an asymmetry factor. The interdomain spacing of phase-separated poly(styrene-b-dimethyl siloxane) has been measured by in situ small angle neutron scattering, both isothermally an at constant ?polymer. The results of these experiments indicate that high-pressure CO2 behaves similarly to a traditional selective liquid solvent. They also show that the isothermally measured d cannot be described by the traditional power law scaling that does not account for solvent selectivity, but collapses to a line when scaled by an asymmetry factor. Data measured at constant ?polymer is in good agreement with previously reported findings, and shows that the scaling is accurate.