Surface and interfacial FTIR spectroscopic studies of latexes. IX. The effect of homopolymer and copolymer structures on surfactant mobility in Sty/BA latices

Abstract

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 F–A or F–S interfaces are surface tension of the substrate, glass transition temperature, water flux during coalescence, and compatibility between latex components. © 1995 John Wiley & Sons, Inc.

Recent advances in stratification and film formation of latex films; attenuated total reflection and step-scan photoacoustic FTIR spectroscopic studies

“…This behavior can be attributed to the ability of SDOSS molecules to migrate preferentially to- ward the F-A interface. Our previous studies 35,36 also indicated that SDOSS migrations are influenced by the surface tension of a substrate and the glass transition temperature (T g ) of the polymer/copolymer. For a higher styrene content, the T g is higher, and the rate of latex coalescence increases.…”

“…35 It appears that the latex stabilization may have a significant effect on the distribution of surfactant molecules across the coalesced latex and that their orientation changes depend upon the stage of coalescence and the water front's moving toward the surface. In these studies, it also became apparent that vibrational spectroscopy, in particular, ATR and step-scan photoacoustic (S 2 -PAS) FTIR spectroscopy, is a powerful tool in determining molecular level features occurring near interfacial regions in latex films.…”

“…Finally, if the surface reactions are favorable, a crosslinked polymer network is formed after coalescence. Niu and Urban 35 demonstrated that there is a significant influence of interfaces on mobility of small molecules in latex films. As a result, various properties, including adhesion, durability, and thermal resistance, may be affected.…”

“…To identify the origin of this phenomenon, let us realize that the presence of the 1056 cm Ϫ1 band was found to be a function of two factors: a particle size and a latex particle composition. 35 As we recall our previous studies 35 conducted on 50%/50% Sty/n-BA latexes with the particle sizes of 100 and 50 nm, the 1056 cm…”

Mechanisms of Particle Deformation During Latex Film Formation

“…It is not, because it determines the mechanisms by which the surfactant will be distributed in the final latex film. And surfactant distributions are extensively studied nowadays because of their strong influence on properties of latex films (18)(19)(20).…”