Fu Xiaohui, Xing Chao, Sun Jing
Key Laboratory of Biobased Polymer Materials, College of Polymer Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, China.
Biomacromolecules. 2020 Dec 14;21(12):4980-4988. doi: 10.1021/acs.biomac.0c01177. Epub 2020 Oct 14.
Bioinspired thermoresponsive polymeric materials with tunable phase-transition behaviors are highly desirable for biomedical applications. Here, we reported a facile approach for the synthesis of both lower critical solution temperature (LCST) and upper critical solution temperature (UCST) types of thermoresponsive polypeptoids with tunable phase-transition temperature in the range of 29--55 °C. The introduction of alkyl groups and ethylene glycol (EG) units results in a controlled phase-transition behavior under fairly mild conditions. A very sharp transition (Δ ≤ 1.5 °C) is observed by simply adjusting pH and the alkyl chain length. In particular, the carboxyl-containing polypeptoids display designable UCST behavior, which can be finely tuned in both water and methanol. All these features make the obtained polymers beneficial for practical applications. More interestingly, we demonstrate that the hydrophilic EG group behaves as an excellent regulator to tune the UCST behavior, while the hydrophobic alkyl residues show remarkable capability to regulate the LCST behavior of the system. We hope that such systematic structure-property studies will enable the design of smart polymer materials to meet the specific needs of future applications.
具有可调相变行为的仿生热响应聚合物材料在生物医学应用中极具吸引力。在此，我们报道了一种简便的方法，用于合成具有29-55°C可调相变温度的下临界溶液温度（LCST）和上临界溶液温度（UCST）类型的热响应性聚肽。引入烷基和乙二醇（EG）单元可在相当温和的条件下实现可控的相变行为。通过简单调节pH值和烷基链长度，可观察到非常尖锐的转变（Δ≤1.5°C）。特别地，含羧基的聚肽表现出可设计的UCST行为，在水和甲醇中均可进行精细调节。所有这些特性使得所获得的聚合物有利于实际应用。更有趣的是，我们证明亲水性EG基团是调节UCST行为的优良调节剂，而疏水性烷基残基对调节体系的LCST行为具有显著能力。我们希望这种系统的结构-性能研究能够推动智能聚合物材料的设计，以满足未来应用的特定需求。
