Polystyrene/poly(n-butyl acrylate) latex blend coalescence, particle size effect, and surfactant stratification: A spectroscopic study

These studies show that polystyrene/poly(n-butyl acrylate) (p-Sty/p-nBA) la tex blend coalescence is inherently affected by latex composition, p-Sty pa rticle size, and the temperature difference between coalescence (T-c) and g lass transition (T-g) temperatures. Sodium dioctylsulfosuccinate (SDOSS) su rfactant molecules are expelled to the film-air (F-A) interface when T-c > T-g of the p-Sty phase. Quantitative attenuated total reflectance Fourier t ransform infrared (ATR FT-IR) analysis shows that SDOSS-H2O concentration l evels near the F-A interface diminish for larger p-Sty latex particle sizes and the magnitude of the SDOSS-COOH interactions near the F-A interface ex hibits similar trends. Furthermore, the amount of SDOSS expelled to the F-A interface is directly proportional to the p-Sty phase surface area. These studies also show that SDOSS hydrophilic ends are preferentially parallel t o the F-A interface, while hydrophobic ends are preferentially perpendicula r.