Synthesis and silicon gradient distribution of emulsifier-free TRIS-containing acrylate copolymer

In this study, a series of emulsifier-free 3-[tris(trimethylsilyloxy)silyl] propyl methacrylate and methyl methacrylate copolymer emulsion was prepared via the semi-continuous technique. The polymerization conditions in the presence of a reactive emulsifier were discussed in detail, and the suitable polymerization condition was provided. Proton nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy proved that emulsifier-free silicon-containing acrylate copolymers were obtained, and silicon content reached 60%. The gradient distribution of silicon in the latex film was characterized by contact angle (CA) analysis, X-ray photoelectron spectroscopy (XPS), and confocal Raman spectroscopy (CRS). CA and XPS results demonstrated the enrichment of silicon at the film–air (F–A) interface in the film that was prepared using an emulsifier-free silicon-containing acrylate copolymer. Furthermore, CRS provided considerable insights into the distribution behavior of silicon in the structure of the film from the F–A interface to the film–glass interface. CRS not only showed that silicon preferentially located at the F–A interface, but also that its distribution behavior was formed in the direction across the film thickness in the sigmoidal model.