polystyreneblockpolymethyl

Polystyrene-block polymethyl methacrylate (PS-b-PMMA) is a diblock copolymer composed of a polystyrene block covalently linked to a poly(methyl methacrylate) block. In the literature the material is usually referred to as PS-b-PMMA, with PMMA representing poly(methyl methacrylate). The two blocks are chemically distinct and typically exhibit limited compatibility, leading to nanoscale phase separation.

PS-b-PMMA is prepared using sequential living polymerization or other controlled methods such as RAFT or ATRP. The PS block is formed first, followed by growth of the PMMA block from the PS macroinitiator. By varying the block lengths and overall molecular weight, researchers control the volume fraction of each block, which in turn determines the self-assembled morphology. Common morphologies include lamellae, cylinders, and spheres, with domain spacings typically in the 10–40 nanometer range for many compositions.

The PS and PMMA blocks have different glass-transition temperatures (PS about 100°C and PMMA about 105°C), imparting thermal stability to PS-b-PMMA. This immiscibility drives microphase separation into well-ordered nanostructures under appropriate processing. Processing often involves solvent or thermal annealing to enhance long-range order and to orient domains for practical use.

Applications of PS-b-PMMA include directed self-assembly for nanopatterning and lithography, where PMMA domains can be selectively removed to reveal nanoporous PS templates. It also serves as a robust resist platform and as a template for inorganic deposition or filtration membranes. PS-b-PMMA is among the most studied block copolymers, providing a versatile model system for nanoscale self-assembly.