Spinodal decomposition in poly(t-butyl acrylate)/polyhedral oligomeric silsesquioxane (POSS) blends confined to thin film geometries

POLY 620

Rituparna Paul, rpaul@vt.edu, Michael C. Swift, miswift@vt.edu, and Alan R. Esker, aesker@vt.edu. Department of Chemistry (0212), Virginia Tech, Blacksburg, VA 24061
Thin films of multicomponent polymer blends containing polymers and solid fillers are utilized for many technological applications. “Filled” polymer thin films are typically not under equilibrium conditions, and their final morphologies and properties are governed by phase separation and wetting. This study utilizes poly(t-butyl acrylate) (PtBA) and trisilanolphenyl-POSS (TPP) blend films to study phase evolution as functions of annealing temperature and time. The results demonstrate that spinodal decomposition ensues at ~70 deg. C during temperature ramp studies for a 60 wt% PtBA blend. The spinodal features coarsen with increasing temperatures and break down to form circular domains at temperatures higher than 130 deg. C. The blend films phase separate immediately via the spinodal mechanism for temperature jump experiments at 75, 85, and 95 deg. C. Power law scaling for the kinetics is consistent with domain growth in the intermediate stages of spinodal decomposition for 60 wt% PtBA blend films.