Cellulose nanocrystals/fluorinated polyacrylate with mechanical tunability, water-oil resistance and self-healing capability via light actuated reversible associations

Traditional fluorinated polyacrylate has been extensively applied in various fields, which is favored by many researchers. However, the polymer usually can lose usefulness when it is damaged. Endowing the polymer with self-healing capability provides a potential solution to address the conflict. Herein, a series of photo actuated selfhealing fluorinated polyacrylate based on coumarin groups was synthesized by reversible addition-fragmentation chain transfer (RAFT)-assisted Pickering emulsion polymerization using the modified cellulose nanocrystals as the stabilizer, n-butyl acrylate (BA) as the soft monomer, and methyl methacrylate (MMA) as the hard monomer. The influences of the dosage of 7-(4-vinylbenzyloxy)-4-methylcoumarin) (VBMC) and the mass ratio of BA to MMA on the emulsion polymerization and latex film properties were studied. The results showed that the latex particle size and its distribution decreased and then increased as the VBMC dosage and the mass ratio of BA to MMA increased. The latex film exhibited not only high ultimate tensile stress (6.36 MPa) and large stretchability (575.71%) but also a certain anti-fatigue characteristic. The water and oil contact angles of latex film could reach 118.5 degrees and 101.7 degrees, respectively. Besides, the latex film could achieve efficient self-healing capability due to the mobility of polymer chains associated with low glass transition temperature (Tg) and the reversible [2+2] cleavage/dimerization reaction of the coumarin groups upon ultraviolet (UV) irradiation of 254 nm and 365 nm. The work offers a substantial reference for developing different light actuated self -healing polymers with great prospects and promising futures.