Tightly Bound PMMA on Silica Has Reduced Heat Capacities

The heat capacities of very small adsorbed amounts of poly(methyl methacrylate) on high-surface-area silica (Cab-O-Sil) were measured using temperature-modulated differential scanning calorimetry (TMDSC) using a quasi-isothermal method and interpreted via different models. The composition-dependent heat capacities of the adsorbed samples were measurably less than those predicted with a simple mixture model. A two-state model, composed of tightly...