SURFACE AND INTERFACIAL FTIR SPECTROSCOPIC STUDIES OF LATEXES .9. THE EFFECT OF HOMOPOLYMER AND COPOLYMER STRUCTURES ON SURFACTANT MOBILITY IN STY/BA LATICES

The effects of homopolymer and copolymer compositions and structures in styrene/n-butyl acrylate (Sty/BA) latices on sodium dioctyl sulfosuccinate (SDOSS) surfactant mobility and its preferential concentration at the film-air (F-A) and film-substrate (F-S) interfaces were examined using attenuated total reflectance Fourier transform infrared (ATR FTIR) spectroscopy. It appears that the SDOSS concentration at the F-S interface is highest when the Sty/BA feed ratio is 50/50, and the excess of Sty results in migration of SDOSS surfactant to the F-A interface. This behavior is attributed to the increased glass transition temperature and diminished compatibility between surfactant molecules and copolymer latex. This study also shows that the primary factors that influence exudation to either FA or F-S interfaces are surface tension of the substrate, glass transition temperature, water flux during coalescence, and compatibility between latex components. (C) 1995 John Wiley & Sons,Inc.