A reversible polymer photoacid with a thermal on/off switch at physiological temperature able to trigger a large pH modulation of its environment is prepared. Light is used to control the acidity of the solution. Additionally, the temperature could be used to modulate the photoacid efficiency, practically turning on and off the ability of the polymer to produce protons. The behavior of this thermoresponsive photoacid copolymer is the result of the combined action of the temperature‐responsive N‐isopropylacrylamide and of a reversible photoacid monomer based on a spiropyran derivative. The acidification of the aqueous medium is activated by irradiation at λ = 460 nm. The reverse reaction is achieved by removing the light stimuli or by exposing the solution to UV‐light. Increasing the temperature above the lower critical solution temperature of the copolymer deactivates the photoacid and irradiation at λ = 460 nm does not lead to the generation of protons or to any detectable change in the pH value of the solution. Hence, the addition of N‐isopropylacrylamide as a comonomer acts as a thermal on/off switch for the photoacid and the coupling of temperature‐and light‐responsiveness in the polyphotoacids yields a “thermophotoacid”.

中文翻译：

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具有开/关热开关的可逆质子发生器

制备了一种可逆的聚合物光酸，该光酸在生理温度下具有热开关，能够触发其环境的大pH调节。光用于控制溶液的酸度。另外，该温度可用于调节光酸效率，实际上开启和关闭聚合物产生质子的能力。这种热响应性光酸共聚物的行为是温度响应性N的共同作用的结果-异丙基丙烯酰胺和基于螺吡喃衍生物的可逆光酸单体。水性介质的酸化通过在λ= 460 nm处辐射而被激活。通过去除光刺激或将溶液暴露在紫外线下可以实现逆反应。将温度升高至共聚物的较低临界溶液温度以上会使光酸失活，并且在λ= 460 nm处进行辐照不会导致质子的产生或溶液pH值的任何可检测变化。因此，添加N-异丙基丙烯酰胺作为共聚单体可作为光酸的热开关，而在多光酸中温度和光响应性的耦合产生了“热光酸”。