Controlled melting of individual, nano-meter-sized, polymer crystals confined in a block copolymer mesostructure

Abstract

We demonstrate a possibility to create custom-made surface patterns on multiple length scales by melting selected. nano-meter-sized polymer crystals confined in a highly ordered, spherical mesostructure of a hydrogenated poly(butadiene-block-ethylene oxide) (PBh-b-PEO) block copolymer. With heatable probes of an atomic force microscope as a heat source, we succeeded to provide highly locally the thermal energy necessary to individually melt such crystals. Besides this possibility for modification of surface properties, we performed detailed in situ studies of thermally induced reorganization processes and subsequent melting of polymer crystals in confined volumes of a block copolymer mesostructure. Close to the melting point, the stability of the confined crystals could be improved by annealing. In addition, the crystal size increased at the expense of already-molten crystals, indicating diffusion of PEO blocks across the highly incompatible PBh matrix.