Emulsion polymerization of super-hydrophobic acrylate enabled by a novel “ferrying” strategy for developing waterborne coatings with reduced surface tension and glossiness

Abstract

The emulsion polymerization of high-alcohol acrylates with extreme hydrophobicity while achieving high monomer conversion has been posed significant challenges. In this study, the emulsion copolymerization of super-hydrophobic stearyl acrylate (SA) with an 18-carbon alkyl group has been successfully conducted by a novel “ferrying” strategy. Specifically, an emulsifier with a 23-carbon alkyl group (hydrophobic) and a 20-oxethyl group (hydrophilic) simultaneously was designed to facilitate the efficient transfer of SA through hydrophobic interaction from monomer drops to micelles, leading to a remarkable improvement in monomer conversion. The self-migration of the 18-carbon alkyl groups grafted onto the copolymer chains, which moved from the inner matrix to the coating surface, resulted in the creation of the waterborne coating with low surface tension during the film formation process. Moreover, it was confirmed that the self-crystallization of the 18-carbon alkyl groups caused the coating to exhibit a self-matting effect with low glossiness. Using an industrial formula, the effects of different types and dosages of emulsifiers, as well as the dosage of SA, on the total monomer conversion, SA conversion, and coating properties were extensively investigated. This work not only broadens the monomer range for emulsion polymerization to highly hydrophobic species, but also provides a variety of industrial waterborne products with low surface tension and low glossiness derived from high-alcohol acrylates, contributing to the development of environmentally friendly chemical industries.