Jingwen Dai

Novel Reversible Mechanochromic Elastomer with High Sensitivity: Bond Scission and Bending-Induced Multicolor Switching

Although the rational designed mechanochromic polymer (MCP) materials have evoked major interest and experienced significant progress recently, it is still a great challenge to develop a facile and effective strategy for preparation of reversible broad-spectrum MCPs with a combination of wide-range color switch ability and high sensitivity, which thus make it possible to mimic gorgeous color change as in nature. Herein, we designed and synthesized a novel rhodamine-based mechanochromic elastomer. Our results demonstrated that the elastomer exhibited very promising and unique properties. Three primary fluorescence colors were presented during continuous uniaxial extension and relaxing process, and reversible broad-spectrum fluorescence color change could be achieved consequently. The fluorescence quantum yield of the opened zwitterion of this new mechanophore was as high as 0.67. In addition, the elastomer showed very high sensitivity to stress with a detectable activation strain of ∼0.24, which was much smaller than those reported in the previous literature reports. Meantime, the easy-to-obtain material, facile preparation, and good mechanical property also made it suitable for potential practical applications.

Xanthate-mediated living/controlled radical copolymerization of hexafluoropropylene and butyl vinyl ether under 60Co γ-ray irradiation and preparation of fluorinated polymers end-capped with a fluoroalkyl sulfonic acid group

Living/controlled radical copolymerization of hexafluoropropylene and butyl vinyl ether has been successfully achieved at room temperature under 60Co γ-ray irradiation in the presence of ethyl 2-(ethoxycarbonothioylthio) acetate. The copolymer end-capped with a sulfonic acid group has been prepared by oxidation of the xanthate end group.

Synthesis and properties of a well-defined copolymer of chlorotrifluoroethylene and N-vinylpyrrolidone by xanthate-mediated radical copolymerization under 60Co γ-ray irradiation

Living/controlled radical copolymerization of chlorotrifluoroethylene and N-vinylpyrrolidone has been successfully achieved at room temperature under 60Co γ-ray irradiation in the presence of ethyl 2-(ethoxycarbonothioylthio)acetate. The living/controlled character of the polymerization was confirmed by GPC and NMR analyses, as well as the chain extension polymerization. The physical properties of the obtained polymers were investigated and the experimental results indicate that the fluorinated copolymer showed excellent film-forming characteristics and high mechanical properties. Moreover, the fluorinated amphiphilic block copolymers prepared by chain extension polymerization show good biocompatibility.

A Diheteroatom Fluoroalkylation Reagent for Preparation of S- and N-Containing Fluoroalkyl Compounds and Sulfonic Acid Polymer

The first stable diheteroatom fluoroalkylation reagent, 2-((2-azido-1-chloro-1,2,2-trifluoroethyl)thio)pyrimidine (ACTP), has been prepared by a novel method. By using this reagent, various fluorinated thioethers and sulfones have been successfully prepared. The dearylation and dearylation-oxidation of fluoroalkyl 2-pyrimidyl sulfone in one-pot reaction were investigated systematically, and the results demonstrated that both fluoroalkyl sulfinates and sulfonates could be obtained in high yields. In addition, ACTP proved to be useful for the preparation of a fluorinated sulfonic acid proton-exchange membrane.