Guo Xiaofeng, Shi Wencheng, Yin Hang, Pan Jiasheng, Wang Zhao, Feng Anchao, Thang San H
State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029, China.
Beijing Key Laboratory of Preparation and Processing of New Polymer Materials, Beijing University of Chemical Technology, Beijing, 100029, China.
Macromol Rapid Commun. 2021 May;42(10):e2000765. doi: 10.1002/marc.202000765. Epub 2021 Apr 26.
Precise polymer architecture and self-assembled morphological control are attractive due to their promising applications, such as drug delivery, biosensors, tissue engineering and "smart" optical systems. Herein, starting from the same hydrophilic units poly(ethylene glycol) (PEG), using CO -sensitive monomer N, N-diethylaminoethyl methacrylate (DEAEMA) and hydrophobic monomer benzyl methacrylate (BzMA), a series of well-defined statistical, block, and gradient copolymers is designed and synthesized with similar degree of polymerization but different monomer sequences by batch and semi-batch RAFT polymerization process and their CO -responsive behaviors of these nano-objects is systematically studied. The gradient copolymers are generated by using semi-batch methods with programmed monomer feed rate controlled by syringe pumps, achieving precise control over desired gradient copolymer composition distribution. In aqueous solution, the copolymers could self-assemble into various aggregates before CO stimulus. Upon bubbling CO , the gradient copolymers preferred to form nanosheet-like structures, while the block and statistical copolymers with similar molar mass could only form larger vesicles with thinner membrane thickness or disassemble. The semi-batch strategy to precisely control over the desired composition distribution of the gradient segment presents an emerging trend for the fabrication and application of stimuli-responsive polymers.
精确的聚合物结构和自组装形态控制因其在药物递送、生物传感器、组织工程和“智能”光学系统等领域的应用前景而备受关注。在此，从相同的亲水性单元聚乙二醇（PEG）出发，使用对CO敏感的单体甲基丙烯酸N，N -二乙氨基乙酯（DEAEMA）和疏水性单体甲基丙烯酸苄酯（BzMA），通过间歇和半间歇可逆加成-断裂链转移（RAFT）聚合过程，设计并合成了一系列具有相似聚合度但单体序列不同的明确的统计共聚物、嵌段共聚物和梯度共聚物，并系统研究了这些纳米对象的CO响应行为。梯度共聚物通过使用半间歇方法生成，通过注射泵控制程序单体进料速率，实现对所需梯度共聚物组成分布的精确控制。在水溶液中，共聚物在CO刺激之前可以自组装成各种聚集体。通入CO后，梯度共聚物倾向于形成纳米片状结构，而具有相似摩尔质量的嵌段共聚物和统计共聚物只能形成膜厚度更薄的较大囊泡或分解。精确控制梯度段所需组成分布的半间歇策略为刺激响应聚合物的制备和应用呈现出一种新趋势。
