Surface self-segregation, wettability, and adsorption behavior of core–shell and pentablock fluorosilicone acrylate copolymers

Abstract

The surfaces of films cast from core–shell fluorosilicone acrylate copolymer (BA/MMA/DFHM and BA/MMA/DFHM/MPTMS/D4) latexes and linear pentablock fluorosilicone acrylate copolymer (PDMS-b-(PMMA-b-PDFHM)2) solutions are intensively investigated and compared by XPS, DCA, AFM, and QCM-D measurements. It is found that the molecular structures and in-solution aggregate structures of these well-defined copolymers have a dramatic influence on the surface structure formation, surface wetting, and adsorption behavior. The PDMS-b-(PMMA-b-PDFHM)2 film cast from chloroform solution with high concentration of low-density unimers is able to perform as strong surface self-segregation of fluorine-containing groups as core–shell copolymer latex films. The BA/MMA/DFHM/MPTMS/D4 in the core–shell latex particles exhibits the less pronounced surface self-segregation of silicon-containing groups than PDMS-b-(PMMA-b-PDFHM)2 due to the occurrence of cross-linking reactions between polysiloxane chains. Indeed, such reactions induce the formation of silica network within the film material, which immobilizes tightly the fluorinated groups on the film surface and thus endows the film with higher surface structural stability for water compared to PDMS-b-(PMMA-b-PDFHM)2 film with similar surface fluorine concentration and even higher silicon concentration. Still, the PDMS-b-(PMMA-b-PDFHM)2 film definitely demonstrates higher advancing and receding contact angles for water than BA/MMA/DFHM/MPTMS/D4 latex film in the case of synergism between surface enrichment of fluorine and silicon.