Department of Chemical Engineering, McMaster University , Hamilton, Ontario, Canada L8S 4L7.
School of Chemistry and Chemical Engineering, South China University of Technology , Guangzhou, Guangdong, China 510640.
ACS Appl Mater Interfaces. 2017 May 3;9(17):15156-15163. doi: 10.1021/acsami.7b04154. Epub 2017 Apr 21.
We prepared force sensitive acrylic latex coatings by covalently incorporating spiropyran mechanophore. The acrylic latexes were obtained through emulsion copolymerization of butyl acrylate (BA), methyl methacrylate (MMA) with vinyltriethoxysilane (VTES) as interparticle cross-linker, and (1'-(2-(methacryloyloxy)ethyl)-3',3'-dimethylspiro[chromene-2,2'-indolin]-6-yl)methyl methacrylate) (SP) as intraparticle cross-linker. The latexes of P(BA-co-MMA-co-SP-co-VTES) were subsequently cast onto Teflon-coated surface to form latex coatings. The condensation of hydrolyzed VTES provided interparticle cross-linking and improved mechanical properties of the formed thin films. Intraparticle cross-linker SP endowed the coatings with mechanoreponsiveness. The mechanoactivation of SP-containing latex films was demonstrated. Increasing the content of intra-cross-linker SP resulted in higher stress sensitivity and lower critical stress required for mechanoactivation. Increasing the content of interparticle cross-linker VTES resulted in higher critical stress for SP mechanoactivation but had little effect on the stress sensitivity. T and operation temperature also showed significant effect on mechanoactivation. Slower strain rate allowed for higher SP-to-MC conversion. This work represents the first example of mechanochromic acrylic latexes and provides insight into the design of force sensitive and self-reporting polymer coatings.
我们通过共价结合螺吡喃机械响应基团制备了力敏性丙烯酸酯乳胶涂料。通过乳液共聚将丙烯酸丁酯 (BA)、甲基丙烯酸甲酯 (MMA) 与乙烯基三乙氧基硅烷 (VTES) 作为粒子间交联剂，以及 (1'-(2-(甲基丙烯酰氧基)乙基)-3',3'-二甲基螺[色烯-2,2'-吲哚]-6-基)甲基甲基丙烯酸酯) (SP) 作为粒子内交联剂，得到了丙烯酸酯乳胶。将 P(BA-co-MMA-co-SP-co-VTES) 的乳液浇铸在特氟龙涂层表面上形成乳胶涂料。水解 VTES 的缩合提供了粒子间交联，并改善了形成的薄膜的机械性能。内交联剂 SP 赋予了涂层机械响应性。展示了含有 SP 的乳胶膜的机械激活。增加内交联剂 SP 的含量会导致更高的应力敏感性和更低的机械激活所需的临界应力。增加粒子间交联剂 VTES 的含量会导致 SP 机械激活的临界应力增加，但对应力敏感性影响不大。T 和操作温度也对机械激活有显著影响。较慢的应变速率允许更高的 SP-to-MC 转化率。这项工作代表了力敏性丙烯酸酯乳胶的第一个例子，并为设计力敏感和自报告聚合物涂料提供了深入了解。
