Tang Yuntao, Zhang Yige, Chen Xi, Xie Xiaowen, Zhou Ning, Dai Zhifeng, Xiong Yubing
Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou, Zhejiang, 310018, China.
Angew Chem Int Ed Engl. 2023 Jan 23;62(4):e202215722. doi: 10.1002/anie.202215722. Epub 2022 Dec 16.
Thermally induced reversible up/down migration of poly(ionic liquid)s (PILs) in aqueous two-phase systems (ATPSs) was achieved for the first time in this study. Novel ATPSs were fabricated using azobenzene (Azo)- and benzyl (Bn)-modified PILs, and their upper and lower phases could be easily tuned using the grafting degree (GD) of the Azo and Bn groups. Bn-PIL with higher GD could go up into the upper phase and Azo-PIL come down to the lower phase when the temperature increased (>65 °C); this behavior was reversed at lower temperatures. Moreover, a reversible two-phase/single-phase transition was realized under UV irradiation. Experimental and simulation results revealed that the difference in the hydration capacity between Bn-PIL and Azo-PIL accounted for their unique phase-separation behavior. A versatile platform for fabricating ATPSs with tunable stimuli-responsive behavior can be realized based on our findings, which can broaden their applications in the fields of smart separation systems and functional material development.
本研究首次实现了聚离子液体（PILs）在水两相系统（ATPSs）中热诱导的可逆上/下迁移。使用偶氮苯（Azo）和苄基（Bn）修饰的PILs制备了新型ATPSs，其上下相可通过Azo和Bn基团的接枝度（GD）轻松调节。当温度升高（>65°C）时，具有较高GD的Bn-PIL可向上进入上相，而Azo-PIL则向下进入下相；在较低温度下这种行为会逆转。此外，在紫外线照射下实现了可逆的两相/单相转变。实验和模拟结果表明，Bn-PIL和Azo-PIL之间水合能力的差异解释了它们独特的相分离行为。基于我们的发现，可以实现一个用于制造具有可调刺激响应行为的ATPSs的通用平台，这可以拓宽它们在智能分离系统和功能材料开发领域的应用。
