Neutron Reflectivity Study of End-Adsorbed Polymer Brushes: Effect of Solvent Quality and Shear Flow
Abstract
We have used neutron reflectometry to study strongly asymmetric PS-PEO block copolymer chains terminally adsorbed onto quartz form d-cyclohexane (marginally good solvent at 45^oC) and d-toluene (althermal solvent). The measurements were taken at various temperatures both below and above the Θ point (22, 33, and 45^oC). The layer thickness was found to increase with improving solvent quality, the volume fraction profile of the polymer being well-described by self-consistent mean field theory. When the brush is subjected to shear flow in toluene, the layer thickness and volume fraction profile remain essentially unchanged up to shear rates of ca. 10,000 s-1. At shear rates of ca. 17,000 s-1, however, there is evidence of substantial polymer desorption.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 1998
- Bibcode:
- 1998APS..MAR.K1113T