文献类型：期刊文献

英文题名：Differences in Cationic and Anionic Charge Densities Dictate Zwitterionic Associations and Stimuli Responses

作者：Shao, Qing[1];Mi, Luo[1];Han, Xia[1,2,3];Bai, Tao[1];Liu, Sijun[4];Li, Yuting[1];Jiang, Shaoyi[1,4]

机构：[1]Univ Washington, Dept Chem Engn, Seattle, WA 98195 USA;[2]E China Univ Sci & Technol, Key Lab Adv Mat, Shanghai 200237, Peoples R China;[3]E China Univ Sci & Technol, Dept Chem, Shanghai 200237, Peoples R China;[4]Univ Washington, Dept Bioengn, Seattle, WA 98195 USA

年份：2014

卷号：118

期号：24

起止页码：6956

外文期刊名：JOURNAL OF PHYSICAL CHEMISTRY B

收录：;EI(收录号：20142617875760);WOS:【SCI-EXPANDED(收录号:WOS:000337784100063)】；

基金：This work was supposed by the National Science Foundation (CMMI-1301435 and CBET-1264477). This work used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation Grant OCI-1053575. Xia Han thanks the financial support of the National Natural Science Foundation of China (Projects 21376073 and 21176065). This work was facilitated through the use of advanced computational, storage, and networking infrastructure provided by the Hyak supercomputer system, supported in part by the University of Washington eScience.

语种：英文

外文关键词：Biological materials - Association reactions

摘要：Zwitterionic materials have shown their excellent performance in many biological and chemical applications. Zwitterionic materials possess moieties that own both cationic and anionic groups. The associations among zwitterionic moieties through electrostatic interactions play an important role in properties of zwitterionic materials. However, the relationship between the molecular structures and associations of zwitterionic moieties are still not well understood. This work compared thermal- and salt-responsive behaviors of sulfobetaine and carboxybetaine polymers by examining their rheological properties as a function of temperature and their hydrodynamic sizes as a function of salt concentration. Results showed that carboxybetaine polymers do not exhibit stimuli responses as expected from the antipolyelectrolyte behavior of zwitterionic polymers as observed in sulfobetaine polymers. We studied and compared the associations among zwitterionic moieties in these two zwitterionic polymers using molecular dynamic simulations. Simulation results show that the charge-density difference between cationic and anionic groups determines the associations among zwitterionic moieties, which are responsible for different stimuli responses of carboxybetaine and sulfobetaine polymers.