Saha Pabitra, Santi Marta, Emondts Meike, Roth Hannah, Rahimi Khosrow, Großkurth Johannes, Ganguly Ritabrata, Wessling Matthias, Singha Nikhil K, Pich Andrij
DWI-Leibniz-Institute for Interactive Materials, Aachen 52056, Germany.
Institute of Technical and Macromolecular Chemistry (ITMC), RWTH Aachen University, Aachen 52074, Germany.
ACS Appl Mater Interfaces. 2020 Dec 30;12(52):58223-58238. doi: 10.1021/acsami.0c17427. Epub 2020 Dec 17.
Fouling on filtration membranes is induced by the nonspecific interactions between the membrane surface and the foulants, and effectively hinders their efficient use in various applications. Here, we established a facile method for the coating of membrane surface with a dual stimuli-responsive antifouling microgel system enriched with a high polyzwitterion content. Different poly(sulfobetaine) (PSB) zwitterionic polymers with defined molecular weights and narrow dispersities were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization and integrated onto poly(-vinylcaprolactam) (PVCL) microgels via a controlled dosage of a cross-linker, adapting a precipitation polymerization technique to obtain a core-shell microstructure. Increasing the PSB macro-RAFT concentration resulted in a shift of both upper critical solution temperature and lower critical solution temperature toward higher temperatures. Cryogenic transmission electron microscopy at different temperatures suggested the formation of a core-shell morphology with a PVCL-rich core and a PSB-rich shell. On the other hand, the significant variations of different characteristic proton signals and reversible phase transitions of the microgel constituents were confirmed by temperature-dependent H NMR studies. Utilizing a quartz crystal microbalance with dissipation monitoring, we have been able to observe and quantitatively describe the antipolyelectrolyte behavior of the zwitterionic microgels. The oscillation frequency of the sensor proved to change reversibly according to the variations of the NaCl concentration, showing, in fact, the effect of the interaction between the salt and the opposite charges present in the microgel deposited on the sensor. Poly(ethersulfone) membranes, chosen as the model surface, when functionalized with zwitterionic microgel coatings, displayed protein-repelling property, stimulated by different transition temperatures, and showed even better performances at increasing NaCl concentration. These kinds of stimuli-responsive zwitterionic microgel can act as temperature-triggered drug delivery systems and as potential coating materials to prevent bioadhesion and biofouling as well.
过滤膜上的污垢是由膜表面与污垢之间的非特异性相互作用引起的，这有效地阻碍了它们在各种应用中的高效使用。在此，我们建立了一种简便的方法，用于在膜表面涂覆富含高聚两性离子含量的双刺激响应性防污微凝胶系统。通过可逆加成-断裂链转移（RAFT）聚合合成了具有确定分子量和窄分散度的不同聚（磺基甜菜碱）（PSB）两性离子聚合物，并通过控制交联剂的用量将其整合到聚（乙烯基己内酰胺）（PVCL）微凝胶上，采用沉淀聚合法获得核壳微观结构。增加PSB大分子RAFT的浓度会导致上临界溶液温度和下临界溶液温度都向更高温度移动。不同温度下的低温透射电子显微镜表明形成了具有富含PVCL的核和富含PSB的壳的核壳形态。另一方面，通过温度依赖性1H NMR研究证实了微凝胶成分的不同特征质子信号和可逆相变的显著变化。利用带有耗散监测的石英晶体微天平，我们能够观察并定量描述两性离子微凝胶的抗聚电解质行为。传感器的振荡频率被证明会根据NaCl浓度的变化而可逆地改变，实际上显示了盐与沉积在传感器上的微凝胶中存在的相反电荷之间相互作用的效果。作为模型表面选择的聚醚砜膜，在用两性离子微凝胶涂层功能化时，表现出受不同转变温度刺激的蛋白质排斥特性，并且在增加NaCl浓度时表现出更好的性能。这类刺激响应性两性离子微凝胶既可以作为温度触发的药物递送系统，也可以作为潜在的涂层材料来防止生物粘附和生物污垢。
