As a probe of the critical driving forces for polymer adhesion, temperature-modulated differential scanning calorimetry (TMDSC) on adsorbed poly(vinyl acetate) (PVAc) on silica has been performed. Three different regions of thermal activity was observed. At low adsorbed amounts, the onset of segmental motion occurred at temperatures significantly higher than glass-transition temperature (T<sub>g</sub>) of the bulk polymer. With increasing the adsorbed amount, two other regions were found at temperatures slightly higher and slightly lower than the T<sub>g</sub> of bulk PVAc. Molecular dynamics simulations were performed to provide insight on the structure of adsorbed PVAc on silica and explain the experimental results. The effect of adsorbed amount and temperature on the structure of PVAc near the silica surface, in the bulk-like polymer region and the polymer/air interface has been analyzed. These effects have been quantified as the number density of carbonyl groups of PVAc as a function of the radial distance from the oxygen atoms on the silica surface and also the orientation of chemical groups at interface. The silica surface modified the polymer structure at the interface and polymer chains formed three different layers evidenced by changes in the number density profile and the orientation of carbonyl groups.

Adsorbed poly(vinyl acetate) on silica: experimental and molecular dynamics simulation studies

249th National Meeting (2015)

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