Phase separation and surfactant stratification in styrene/n-butyl acrylatecopolymer and latex blend films. 17. A spectroscopic study

These studies focus on behavior of sodium dioctylsulfosuccinate (SDOSS) sur factant molecules in styrerie/n-butyl acrylate (Sty/n-BA) copolymers and bl ended latexes. Using a combination of IR and Raman spectroscopic and microa nalytical techniques, not only stratification of SDOSS surfactant molecules across latex film thickness can be assessed. but also the effect of latex composition on coalescence can be analyzed. For Sty/n-BA latex copolymers, SDOSS ... H2O, SDOSS ... COOH associations, and free SDOSS are formed at th e film-air (F-A) interface and exhibit nonuniform distributions across the film thickness. However, for p-Sty/p-nBA latex polymer blends, SDOSS is dis tributed uniformly at the F-A interface, and its concentration levels are s ignificantly lower when compared to Sty/n-BA copolymer latexes. These studi es show that, while step-scan photoacoustic Fourier transform infrared (SS- PAS FTIR) and attenuated total reflectance (ATR) FT-IR are effective depth profiling methods for latex, films, FT-IR and FT-Raman imaging techniques p rovide unique analytical facilities far typically nondistinguishable surfac e latex components.