Tonegawa Asato, Tamura Atsushi, Yui Nobuhiko
Department of Organic Biomaterials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University (TMDU), 2-3-10 Kanda-Surugadai, Chiyoda, Tokyo, 101-0062, Japan.
Macromol Rapid Commun. 2020 Sep;41(17):e2000322. doi: 10.1002/marc.202000322. Epub 2020 Aug 7.
Stimuli-responsive materials have received considerable attention for their application in biomedical fields. Herein, the temperature-dependent phase transition behavior of acetylated polyrotaxanes (Ac-PRXs) consisting of acetylated cyclodextrins threaded onto a linear axle polymer in aqueous solution is investigated. The aqueous solutions of Ac-PRXs exhibit temperature-dependent transmittance changes when the degree of acetylation is 30-40%. Upon increasing the temperature, Ac-PRXs are dehydrated and acetyl groups are subsequently associated through hydrophobic interactions. Interestingly, the Ac-PRXs form coacervate droplets with a diameter of ≈2-3 µm above their cloud points. These temperature-responsivities of Ac-PRXs are observed for other PRXs with different axle polymer molecular weights and compositions. Consequently, the acetylation of PRXs is an attractive chemical modification for yielding temperature-responsivities, and Ac-PRXs can be applied as temperature-responsive supramolecular materials.
刺激响应性材料因其在生物医学领域的应用而受到广泛关注。在此，研究了由乙酰化环糊精穿在线性轴聚合物上构成的乙酰化聚轮烷（Ac-PRXs）在水溶液中的温度依赖性相变行为。当乙酰化程度为30-40%时，Ac-PRXs的水溶液表现出温度依赖性的透光率变化。随着温度升高，Ac-PRXs脱水，随后乙酰基团通过疏水相互作用缔合。有趣的是，Ac-PRXs在其浊点以上形成直径约为2-3 µm的凝聚层液滴。对于具有不同轴聚合物分子量和组成的其他PRXs，也观察到了Ac-PRXs的这些温度响应性。因此，PRXs的乙酰化是一种产生温度响应性的有吸引力的化学修饰方法，Ac-PRXs可作为温度响应性超分子材料应用。
