Pruthi Vaishali, Akae Yosuke, Théato Patrick
Institute for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology, Engesserstraße 18, 76128, Karlsruhe, Germany.
Research Fellow of Japan Society for the Promotion of Science, Tokyo, 102-0083, Japan.
Macromol Rapid Commun. 2023 Oct;44(19):e2300270. doi: 10.1002/marc.202300270. Epub 2023 Jul 5.
Herein, novel photoresponsive spiropyran (SP)-based P(DEGMA-co-SpMA) copolymers with variable percentages of SP fractions are synthesized. The SP group present in these polymers exhibited the abilities of reversible photoisomerism. Their photoresponsive, structural, and thermal properties have been investigated and compared using various characterization techniques. These light-responsive copolymers are found to exhibit photoswitchable glass transition temperature (T ), high thermal stability (T > 250°C), instant photochromism as well as fluorescence upon exposure to UV light. It is demonstrated that the T of these synthesized polymers increased when irradiated with UV light (λ = 365 nm), as a consequence of the photoisomerization of incorporated SP groups into their merocyanine form. This increase in T is attributed to an increase in polarity and a decrease in the overall entropy of the polymeric system when it switches from the ring-closed SP form (less-ordered state) to the ring-opened merocyanine form (more-ordered state). Therefore, such polymers with a unique feature of phototunable glass transition temperatures provide the possibility to be integrated into functional materials for various photoresponsive applications.
在此，合成了具有不同SP分数百分比的新型基于光响应螺吡喃（SP）的P（DEGMA-co-SpMA）共聚物。这些聚合物中存在的SP基团表现出可逆光异构化能力。使用各种表征技术对它们的光响应、结构和热性能进行了研究和比较。发现这些光响应共聚物表现出可光开关的玻璃化转变温度（T）、高热稳定性（T>250°C）、即时光致变色以及在紫外光照射下的荧光。结果表明，由于掺入的SP基团光异构化为其部花青形式，这些合成聚合物在紫外光（λ=365nm）照射下T升高。T的这种升高归因于聚合物体系从闭环SP形式（无序状态）转变为开环部花青形式（更有序状态）时极性增加和总熵降低。因此，这种具有光可调玻璃化转变温度独特特征的聚合物为集成到用于各种光响应应用的功能材料中提供了可能性。
