Multiresponsive, Critical Gel Behaviors of Polyzwitterion-Polyoxometalate Coacervate Complexes
Multiresponsive, Critical Gel Behaviors of Polyzwitterion-Polyoxometalate Coacervate Complexes
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DOI：
10.1021/acs.macromol.8b01759
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发表时间：
2018-11-27
期刊：
影响因子：
5.5
通讯作者：
Zhu, Yingxi
中科院分区：
文献类型：
--
作者：
Jing, Benxin;Xu, Donghua;Zhu, Yingxi
通过自发液-液分离进行大分子凝聚络合已成为在水介质中制备新型功能纳米材料的一种简便的超分子组装方法。与传统的聚电解质凝聚体不同，净中性两性离子聚合物与无机阴离子纳米多金属氧酸盐(POMS)在盐溶液中形成的凝聚络合物具有独特的盐硬化和临界凝胶行为，由于添加了POMS，显著提高了粘弹性。流变学和光漂白后荧光恢复(FRAP)结果表明，POM大离子不仅参与凝聚络合，而且作为交联剂调节刺激响应的凝胶状微结构，产生最稳定和最强凝聚络合的最佳POM与聚两性离子的摩尔比。重要的是，凝胶状凝聚复合体的粘弹性强度和网孔大小可以通过POM、盐浓度和温度在几个数量级上进行调节，这为为实际应用定制聚合物-POM凝聚复合体的材料性能提供了前所未有的高可调性。
Macromolecular coacervate complexation via spontaneous liquid-liquid separation has become a facile supramolecular assembly approach to produce new functional nanomaterials in aqueous media. Distinct from conventional polyelectrolyte coacervates, the coacervate complexes formed between net neutral zwitterionic polymers and inorganic anionic nanometer-scaled polyoxometalates (POMs) in salted solutions exhibit unique salt hardening and critical gel behaviors with significantly enhanced viscoelasticity due to added POMs. Rheology and fluorescence recovery after photobleaching (FRAP) results suggest that POM macroions not only participate in coacervate complexation but also work as cross-linkers to modulate the stimuli-responsive gel-like microstructure, yielding an optimal POM-to-polyzwitterion molar ratio for the most stable and strongest coacervate complexation. Importantly, the viscoelastic strength and mesh pore size of gel-like coacervate complexes can be tuned over several orders of magnitude by POM and salt concentrations and temperature, which offers unprecedentedly high tunability to tailor the material properties of polymer-POM coacervate complexes for practical applications.