Abstract：
The properties of polyzwitterions are closely linked to their carbon spacer length (CSL) between oppositely charged groups. A thorough understanding of the effect of CSL on the properties of polyzwitterion-functionalized membranes is important for their fouling resistance and separation performances. In this work, polyzwitterion-functionalized membranes with different CSLs are prepared by coupling selective swelling-induced pore generation with zwitterionization, and the investigation is focused on comprehending the molecular mechanisms underlying protein resistance and conformational transitions within polyzwitterions under varying CSLs. The zwitterionized films show an enhancement in the surface negative potential with the increase of CSL, attributed to the negatively charged groups distanced from the positively charged groups. Quartz crystal microbalance with dissipation (QCM-D) demonstrates that zwitterionized films with different CSLs display distinct levels of resistance to protein adsorption. The trimethylamine N-oxide-derived polymer (PTMAO, CSL = 0) zwitterionized film shows the highest resistance compared to the poly(3-[dimethyl(2\'-methacryloyloxyethyl] ammonio) ethanesulfonate (PMAES, CSL = 2) zwitterionized film and the poly(sulfobetaine methacrylate) (PSBMA, CSL = 3) zwitterionized film, owing to its electrical neutrality and pronounced hydrophilicity. Moreover, analysis of the anti-polyelectrolyte behaviors reveals that PTMAO does not undergo a significant conformation transition in deionized water and salt solutions, while the conformations of PMAES and PSBMA display to be more salt-dependent as the CSL increases, attributed to their increased polarization and dipole moment. As a result, the permeability of zwitterionized membranes exhibits enhanced salt responsiveness with the increase in CSL. The findings of this study are expected to facilitate the design of adsorption-resistant surfaces desired in diverse fields.
摘要：
多两性离子的性质与其带相反电荷的基团之间的碳间隔长度（CSL）密切相关。全面了解CSL对聚两性离子功能化膜性能的影响对于其抗结垢性和分离性能很重要。在这项工作中,通过将选择性溶胀诱导的孔生成与两性离子耦合，制备具有不同CSL的多两性离子功能化膜，这项研究的重点是理解不同CSL下聚两性离子中蛋白质抗性和构象转变的分子机制。随着CSL的增加，两性离子薄膜的表面负电势增强，归因于带负电荷的基团远离带正电荷的基团。具有耗散的石英晶体微天平（QCM-D）表明，具有不同CSL的两性离子膜对蛋白质吸附的抵抗力不同。三甲胺N-氧化物衍生的聚合物(PTMAO，与聚（3-[二甲基（2'-甲基丙烯酰氧基乙基]铵）乙磺酸盐（PMAES，CSL=2）两性离子膜和聚（磺基甜菜碱甲基丙烯酸酯）（PSBMA，CSL=3)两性离子薄膜，由于其电中性和明显的亲水性。此外，抗聚电解质行为的分析表明，PTMAO在去离子水和盐溶液中不会发生明显的构象转变，虽然随着CSL的增加，PMAES和PSBMA的构象显示出更多的盐依赖性，归因于它们增加的极化和偶极矩。因此,随着CSL的增加，两性离子膜的渗透性表现出增强的盐响应性。这项研究的结果有望促进不同领域所需的抗吸附表面的设计。
