作者：Chi Li, Jin Jing, Yanxiong Pan, Xiangling Ji, Wei Jiang
关键字：环形聚合物刷, 热响应, 金纳米粒子, 胶体稳定性, 释放性能
论文来源：期刊
具体来源：Nanoscale, 2025, 17(12), 7313-7323
发表时间：2025年

摘要：缺乏链端的环形聚合物刷表现出独特的拓扑结构和相关性质。虽然溶液中的环形聚合物刷已被广泛研究，但热响应聚合物接枝到纳米粒子表面后的拓扑及其相应性能鲜有报道。本文用单硫醇和双硫醇封端的聚N-异丙基丙烯酰胺（PNIPAAm）分别修饰金纳米粒子（AuNPs），制备线性和环形PNIPAAm刷包覆AuNPs，详细评估了PNIPAAm刷拓扑对热响应行为、胶体稳定性和释放性能的影响。与线性对应物相比，环形聚合物在加热-冷却温度循环中表现出相对较高的胶体稳定性和快速热响应行为，从而在温度变化时触发更明显的染料分子释放；即使释放首先在25°C达到饱和，升高至45°C后仍可再次触发。相比之下，线性聚合物刷因链缠结而未表现出明显触发行为。该工作展示了聚合物刷拓扑如何影响热响应纳米粒子的稳定性和温度响应行为，为环形温度敏感聚合物刷的表面改性提供了新机会。

Abstract：Looped polymer brushes lacking chain terminals exhibited unique topological structures and associated properties. Looped polymer brushes in solution have been extensively studied, although the topology and corresponding performances of the thermal-responsive polymer upon grafting onto nanoparticle surfaces have been hardly reported. In this work, gold nanoparticles (AuNPs) were modified using poly(N-isopropyl acrylamide) (PNIPAAm) terminated with one thiol and two thiol groups to prepare linear and looped PNIPAAm brush-coated AuNPs, respectively. The effect of the topology of PNIPAAm brushes on thermal-responsive behavior, colloidal stability and release performances was evaluated in detail. Compared to the linear counterparts, the looped polymer exhibits relatively higher colloidal stability and rapid thermal-responsive behavior during heating-cooling temperature cycling. This resulted in a more pronounced release of dye molecules triggered by the looped one upon temperature change, and even if the release is first saturated at 25°C, it is triggered again by raising the temperature to 45°C. In contrast, the linear polymer brushes did not show significant triggering behavior due to chain entanglement. This work demonstrated how the polymer brush topology affected thermal-responsive nanoparticles'' stability and temperature-responsive behavior, which may provide new opportunities for surface modification of looped polymer brushes with temperature-sensitive properties.

论文链接：https://doi.org/10.1039/d4nr05205f