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Tuning the Negative Photochromism of Water-Soluble Spiropyran Polymers
Macromolecules ( IF 5.1 ) Pub Date : 2018-10-03 00:00:00 , DOI: 10.1021/acs.macromol.8b01915 Matthew J. Feeney 1 , Samuel W. Thomas 1
Macromolecules ( IF 5.1 ) Pub Date : 2018-10-03 00:00:00 , DOI: 10.1021/acs.macromol.8b01915 Matthew J. Feeney 1 , Samuel W. Thomas 1
Affiliation
In aqueous media, negative photochromism can occur from cationic, protonated merocyanines (MCH+) to spiropyrans (SP) upon exposure to visible light. Herein, we demonstrate the uniquely simple manner in which polymers can tune the key properties of these photochromes through copolymer preparation. Nine water-soluble, SP-containing polymers yield wide ranges of key properties for negative photochromism—accessible MCH+ pKa values spanning 5 pH units, quantum yields of photochemical ring closure up to 0.2, and rates of thermal equilibration ranging 2 orders of magnitude. In buffered solutions, many of these polymers showed photostationary states with greater than 80% conversion to SP and no detectable photochromic fatigue over 15 cycles. These results demonstrate the potential for tuning key properties of the MCH+ photochrome through both the spiropyran pendants themselves and the water-solubilizing comonomers. The dependence of MCH+ pKa on comonomer structure enabled tunable range of pH for reversible photoacid activity using a single spiropyran derivative, further showcasing the versatility of water-soluble photochromic polymers.
中文翻译:
调整水溶性Spiropyran聚合物的负光致变色性
在水性介质中,暴露于可见光时,阳离子质子化的花青素(MCH +)到螺吡喃(SP)会发生负光致变色现象。在这里,我们演示了独特的简单方法,其中聚合物可以通过共聚物制备来调节这些光致变色剂的关键性能。九种水溶性,含SP的聚合物可产生广泛的负光致变色关键特性-可访问的MCH + p K a值跨越5个pH单位,光化学闭环的量子产率高达0.2,热平衡速率达2个数量级。在缓冲溶液中,这些聚合物中的许多聚合物显示出光平稳状态,并具有超过80%的SP转化率,并且在15个循环中没有可检测到的光致变色疲劳。这些结果证明了通过螺吡喃酮侧基本身和水溶性共聚单体调节MCH +荧光染料关键特性的潜力。MCH + p K a对共聚单体结构的依赖性使得使用单个螺吡喃衍生物可调节的pH范围可逆的光酸活性,进一步显示了水溶性光致变色聚合物的多功能性。
更新日期:2018-10-03
中文翻译:
调整水溶性Spiropyran聚合物的负光致变色性
在水性介质中,暴露于可见光时,阳离子质子化的花青素(MCH +)到螺吡喃(SP)会发生负光致变色现象。在这里,我们演示了独特的简单方法,其中聚合物可以通过共聚物制备来调节这些光致变色剂的关键性能。九种水溶性,含SP的聚合物可产生广泛的负光致变色关键特性-可访问的MCH + p K a值跨越5个pH单位,光化学闭环的量子产率高达0.2,热平衡速率达2个数量级。在缓冲溶液中,这些聚合物中的许多聚合物显示出光平稳状态,并具有超过80%的SP转化率,并且在15个循环中没有可检测到的光致变色疲劳。这些结果证明了通过螺吡喃酮侧基本身和水溶性共聚单体调节MCH +荧光染料关键特性的潜力。MCH + p K a对共聚单体结构的依赖性使得使用单个螺吡喃衍生物可调节的pH范围可逆的光酸活性,进一步显示了水溶性光致变色聚合物的多功能性。