Influence of PDI and composition ratio for micro phase separation about PS-b-PMMA block copolymer

We have successfully synthesized polystyrene(PS)-b-polymethylmethacrylate (PMMA) block copolymer that is precious with controlled molecular weight, PDI and composition ratio by living anionic polymerization method using large-scale apparatus. In addition, the influence of PDI, composition ratio and composition distribution for micro phase separation about PS-b-PMMA block copolymer is investigated. The results show that PDI is the major factor for defect, while composition ratio and composition distribution has influence for morphology. As PDI increase 1.06 to 1.13, also defects are increased a lot. As composition ratio of PS increase 51% to 60%, micro phase separation structure was changed from lamella to gyroid. Moreover, we surmised that these properties have a boundary of influence towards micro phase separation. Therefore, is necessary to control these properties by living anionic polymerization in order to use DSA materials in semiconductor process.