A Challenge to the Micro-phase Separation Limit of PS-b-PMMA by Doping with Hydrophilic Materials

Abstract

We examined effects of doping with hydrophilic materials on micro-phase separation of polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA). As the hydrophilic materials, three organic acid compounds; butane -1,2,3,4- tetracarboxylic acid (BTA), cyclobutane -1,2,3,4- tetracarboxylic acid (CBTC), and sulfonyl-4,4'-diphenol (SNDP) were utilized in this experiment. By adding them to the PS-b-PMMA, it was found that they induced reducing phase-separation size. The doping of organic acid compounds into PS-b-PMMA decreased the phase separation size, while increasing doping PMMA homopolymer increased it. The PS-b-PMMA with low molecular weight PS 10.0 kg/mol -b- PMMA 10.0 kg/mol was utilized to examine the effect for phase-separation limit. By doping with 5 wt% of CBTC PS-b-PMMA showed lamellar structure with 8.2 nm half pitch. We considered that the doping organic acid compounds were a promising path for overcoming the phase-separation limit in PS-b-PMMA.