Surfactant addition effects on dispersion and microdomain orientation in SBS triblock copolymer/alumina nanoparticle composites

The aim of this study was to investigate the effects of surfactant addition on the dispersion of 1-3 wt.% alumina nanoparticles on the self-assembled morphology of poly(styrene-b-butadiene-b-styrene) (SBS) linear triblock copolymer. The neat triblock copolymer microphase separated into PS cylinders self-assembled on a hexagonal array in the PB matrix, being the orientation of domains dependent on the annealing conditions. UV-vis and AFM analyses showed an improvement on dispersion of Al2O3 nanoparticles into SBS matrix by adding dodecanethiol as organic surfactant, due to its miscibility with PS block. Interactions between surfactant-coated Al2O3 nanoparticles with PS block were demonstrated by the variation on the glass transition temperature of this block. AFM analysis showed that the incorporation of surfactant-coated Al2O3 nanoparticles in the SBS matrix have great influence on the orientation of microphase separated domains in SBS nanocomposites.