The effect of dispersion of inorganic nanoparticles on the phase behavior of block copolymers in a selective solvent using SANS was analyzed. The nanoparticles were purified using methanol to remove the residual ions and unbound thiol groups. SANS experiments were performed on samples sealed in 1 mm path length quartz cells using the time-of-flight SAND instrument at the Intense Pulsed Neutron Source. in the neat copolymer solution, the phase behavior is governed by the polymer/polymer and polymer/solvent interactions. In the PS-PVP /Au complex solution an additional long-range interaction due to the presence of nanoparticles in PS domains arises. The thermodynamic equilibrium in this solution, therefore is governed by the balance between the interactions between the PS and PVP blocks and their interaction with the solvent and the confined nanoparticles. The inability of the nanoparticles to readily diffuse out of the favorable domain at elevated temperature constrains the interfacial curvature, causing slow transitions in the block copolymer phase behavior.
All Science Journal Classification (ASJC) codes
- Materials Chemistry