Synthesis and characterization of cationic fluorinated polyacrylate soap-free latexes with core-shell structure

Cationic fluorinated polyacrylate soap-free latexes (CFMBD) with core-shell structure were prepared by co-polymerizing dodecafluoroheptyl methacrylate (DFMA), methyl methacrylate (MMA), butyl acrylate (BA), and dimethylaminoethyl methacrylate (DM) using a novel cationic polymerisable emulsifier, maleic acid double ester-octadecyl poly(ethyleneoxy)₂₀ ether-ethylene trimethyl ammonium chloride (R303). FT-IR spectra and ¹H-NMR spectra confirmed that DFMA successfully participated in emulsion polymerization. The resulted emulsion particles had a core-shell structure. Compared with the latex prepared by mixed 1831/AEO-9 emulsifiers, the latexes prepared by R303 emulsifier had higher surface tension. In addition, hydrophobicity of the CFMBD latex film was superior to that of the general latex film under the same conditions. Those latex films showed the increasing thermal stability with augment of DFMA amount in polymer compared to fluorine-free one. XPS analysis indicated the fluoroalkyl groups had the tendency to enrich at the film-air interface. The fluorine-free latex film showed the relatively smooth surface morphology in its AFM image, however, there were numerous little protuberances on the film surface of the CFMBD latex from the polymer containing 27.5 wt% DFMA in total monomers weight dried at room temperature. Especially, after the annealing process, some peaks and lots of protuberances on that film appeared and the surface roughness was greatly increased. Water contact angles (WCAs) of fluorine-free latex film, that CFMBD film dried at room temperature and after the annealing process could attain 62.5°, 102.5° and 108.5°, respectively.