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) latex blend coalescence is inherently affected by latex composition, p-Sty particle size, and the temperature difference between coalescence (Tc) and glass transition (Tg) temperatures. Sodium dioctylsulfosuccinate (SDOSS) surfactant molecules are expelled to the film−air (F−A) interface when Tc > Tg of the p-Sty phase. Quantitative attenuated total reflectance Fourier transform infrared (ATR FT-IR) analysis shows that SDOSS−H2O concentration levels 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 exhibits 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 to the F−A interface, while hydrophobic ends are preferentially perpendicular.