Cellulose nanocrystals/fluorinated polyacrylate with mechanical tunability and self-healing capability via photo actuated reversible associations

Abstract

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 self-healing fluorinated polyacrylate based on coumarin groups was synthesized by Pickering emulsion polymerization using the cellulose nanocrystals (CNCs) as the stabilizer, n-butyl acrylate (BA) as the soft monomer, and methyl methacrylate (MMA) as the hard monomer. The influences of the amount of 7-(4-vinylbenzyloxy)-4- methylcoumarin) (VBMC) and the mass ratio of BA and 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 BA/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. Besides, the latex film can 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 photo-actuated self-healing polymers with great prospects and promising futures.