Altering the Self-Assembly of Poly(styrene-block-methyl methacrylate) by Introduction of Strongly Dissimilar Molecules at the Block Interface

A triblock copolymer (triBCP) containing a short glycidyl methacrylate (GMA) middle block was chemically altered using the efficient thiol-epoxy ring-opening reaction. The resultant modified triBCPs showed significantly different self-assembly behavior from that of the parent triBCP. Analysis by SAXS and TEM showed that this technique can be used to modify the effective interaction parameter (chi(eff)) and the self-assembled morphology in the bulk. When modified with strongly interacting hydroxyl groups, chi(eff) was found to have increased by a factor of 5. By introducing fluorinated liquid-crystalline molecules, the self-assembled morphology changed from purely lamellar to a complex mixture of lamellae and tetragonally packed cylinders with domain spacing of 20.4 nm and 14.6 nm respectively.