Aqueous solution behavior of thermoresponsive polyzwitterionic microgels based on poly(N-vinylcaprolactam) synthesized via RAFT precipitation polymerization
Aqueous solution behavior of thermoresponsive polyzwitterionic microgels based on poly(N-vinylcaprolactam) synthesized via RAFT precipitation polymerization
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DOI：
10.1016/j.eurpolymj.2019.05.063
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发表时间：
2019-09
影响因子：
6
通讯作者：
Pabitra Saha;Michael Kather;S. L. Banerjee;N. Singha;A. Pich
中科院分区：
文献类型：
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作者：
Pabitra Saha;Michael Kather;S. L. Banerjee;N. Singha;A. Pich
采用可逆加成-破碎链转移（RAFT）沉淀聚合技术合成两性离子聚磺基甜菜碱（PSB）链修饰的刺激响应型聚n -乙烯基己内酰胺（PNVCL）微凝胶。以磺胺甜菜碱（SB）为原料，采用RAFT聚合法制备了分子量可控的聚两性离子PSB大筏。采用该方法，可以获得分子量可控的大筏。将不同分子量（1000、5000、10000 g/mol）和浓度（1、2、2.5 mol%）的PSB宏观raft与不同量的交联剂N′-亚甲基双丙烯酰胺（BIS）（1.5、2.5 mol%）一起用于PNVCL微凝胶的沉淀聚合，得到不同量的可控长度和可变交联度的表面接枝多两性离子链。通过FTIR和1h NMR表征了PSB宏筏成功掺入PNVCL微凝胶。增加PNVCL微凝胶中PSB浓度和BIS含量，导致电泳迁移率（µe）和体积相变温度（VPTT）呈线性增加。然而，增加两性离子宏观raft的分子链长度会导致VPTT向低温方向转移。这种具有刺激反应性、多两性离子修饰的PNVCL微凝胶具有潜在的生物医学应用前景。
A new route to synthesize stimuli-responsive poly(N-vinylcaprolactam) (PNVCL) microgels decorated with zwitterionic poly(sulfobetaine) (PSB) chains was developed, using reversible addition–fragmentation chain transfer (RAFT) precipitation polymerization. The polyzwitterionic PSB macro-RAFTs of controlled molecular weight were synthesized by RAFT polymerization of sulfobetaine (SB). Using this method, macro-RAFTs with good control over the molecular weight could be achieved. The PSB macro-RAFTs, having different molecular weights (1000, 5000, 10,000 g/mol) and concentrations (1, 2, 2.5 mol%), were used along with different amount of the cross-linkerN,N'-methylenebisacrylamide (BIS) (1.5 and 2.5 mol%) in the precipitation polymerization of PNVCL microgels to obtain varying amounts of surface-grafted polyzwitterionic chains of controlled length and variable cross-linking degrees. The successful incorporation of PSB macro-RAFTs into PNVCL microgels was characterized by FTIR and1H NMR studies. Increasing the PSB concentration and BIS content in the PNVCL microgels resulted in a linear increase in electrophoretic mobility (µe) and volume phase transition temperature (VPTT). However, increasing the molecular chain length of the zwitterionic macro-RAFT resulted in a shift of VPTT towards lower temperatures. This kind of stimuli-responsive, polyzwitterion decorated PNVCL microgels can be a potential material for biomedical applications.