Effect of water on polymer diffusion in latex films

TLDR: The role of water in polymer diffusion in latex films was examined in this paper, where it was shown that water absorption in PBMA latex films does increase film turbidity, both for nascent and for well-annealed films.

Abstract: The role of water in polymer diffusion in latex films was examined. For a hydrophobic polymer (poly(butyl methacrylate), PBMA), water has little influence on the polymer diffusion rate. Water absorption in PBMA latex films does increase film turbidity, both for nascent and for well-annealed films. For a hydrophilic polymer (a copolymer of 5 wt % methacrylic acid and 95 wt % butyl methacrylate, P(MAA-co-BMA)], the presence of water (e.g., 5 wt %) increases the diffusion coefficient by a factor of 5 at 60 °C. Upon neutralization of the carboxylic acid groups of P(MAA-co-BMA) with NaOH, the polymer diffusion is much retarded in dry films but greatly enhanced in wet films:  the polymer diffusion coefficients for the wet films are about 2 orders of magnitude larger than those for the corresponding dry films. Neutralization with NH3 results in intermediate diffusion rates, between those of unneutralized and NaOH-neutralized films under both dry and wet conditions.