Fine-tuning in-plane interdomain spacing of polystyrene-b-poly(ethene-co-butadiene)-b-polystyre ne triblock copolymer adding monodisperse polystyrene

The influence of adding narrow molar mass distribution polystyrene (PS) homopolymer on the morphology and/or dewetting processing of polystyrene-b-poly(ethene-co-butadiene)-b-polystyrene triblock copolymer (SEBS) thin films was investigated. The addition of the homopolymer caused a transition from non-straight ribbons (with regularly spaced necks) to a spherical microdomain structure for an amount of 75 vol% PS (SEBS/PS 1:3), which also shows an interdomain distance increase of three times with respect to the neat SEBS. This spacing and interdomain distance control coincides with the amount of homopolymer added in the blend. The blending with PS demonstrates an approach to fine-tuning the block copolymer structure and tailoring in-plane microdomain spacing. Smaller or higher amounts of PS changed the spontaneous patterned structure originally observed for the neat triblock copolymer, resulting in a non-ordered microphase separation. (c) 2023 Society of Industrial Chemistry.