Tuning the color switching of naphthopyrans via the control of polymeric architectures
作者:Wilasinee Sriprom、Marjorie Néel、Christopher D. Gabbutt、B. Mark Heron、Sébastien Perrier
DOI:10.1039/b617865k
日期:——
A range of polymerisable photochromic naphthopyrans were prepared via the synthesis of an acrylate moiety on either the naphthalene ring (R) and/or the di-aryl (Ar) rings on the 3-position of the naphthopyran. The monomers obtained (NA) were copolymerised with methyl methacrylate (MMA) and methyl acrylate (MA) by the RAFT (reversible addition fragmentation chain transfer) process in order to control the structure of the polymeric chains and accurately control the number of photochromic molecules per chain. Films were prepared with the synthesized photochromic polymers and their photochromic properties were assessed. We found that the fading rate of the photochromic dye was slower in a matrix of PMMA (higher Tg) than in a matrix of PMA (lower Tg). By producing block copolymers of PMMA-b-poly(MA-co-NA), the fading rate was increased, and the production of PS-b-poly(MA-co-NA) further enhanced the speed of switching, as phase separation occurred between the poly(MA-co-NA) block and the PS block. This study presents an example of tuning the photochromic properties of a dye via variation of the architecture of its polymeric support.
一系列可聚合的光致变色萘吡喃通过在萘环(R)和/或二芳基(Ar)环的3位上合成丙烯酸酯基团来制备。获得的单体(NA)通过RAFT(可逆加成断裂链转移)过程与甲基丙烯酸甲酯(MMA)和丙烯酸甲酯(MA)共聚,以控制聚合物链的结构并精确控制每条链上的光致变色分子数量。制备了合成的光致变色聚合物薄膜并评估了它们的光致变色性能。我们发现,光致变色染料在PMMA(高Tg)基质中的褪色速率比在PMA(低Tg)基质中慢。通过制备PMMA-b-聚(MA-co-NA)嵌段共聚物,褪色速率增加,而制备PS-b-聚(MA-co-NA)进一步提高了开关速度,因为聚(MA-co-NA)嵌段和PS嵌段之间发生了相分离。这项研究展示了一个通过改变染料聚合物支撑结构的实例来调谐光致变色性能。