Directed Morphology of Nanofilled Polymer Films on Flexible Substrates

We demonstrate viable meso-patterning techniques that have relevance to electronics and organic photovoltaic applications via tunable control of polymer thin film instabilities. To this end, we examine the influence of fullerene (C$_{60}$) nanoparticles on multicomponent polymer thin films on patterned and flexible polydimethylsiloxane substrates and compare these results to morphologies on hard silica xerogel substrates of variable roughness and surface energy. Controlled incorporation of nanoparticles (NPs) can be used to tune polymer thin film instabilities and morphology. At NP concentrations below a threshold value, we observe directed dewetting of blend thin films consisting of uniformly aligned dewet domains that mimic the periodicity of the confining media, consistent with our previous experiments where it was observed that C$_{60}$ NPs preferentially segregate to a PS/PB blend interface up to a certain saturation concentration.