Zhao Xiaoli, Xu Zhen, Xie Yang, Zheng Bingna, Kou Liang, Gao Chao
Ministry of Education (MOE) Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University , 38 Zheda Road, Hangzhou, Zhejiang 310027, People's Republic of China.
Langmuir. 2014 Apr 8;30(13):3715-22. doi: 10.1021/la500553v. Epub 2014 Mar 28.
Stabilization of colloids is of great significance in nanoscience for their fundamental research and practical applications. Electrostatic repulsion-stabilized anisotropic colloids, such as graphene oxide (GO), can form stable liquid crystals (LCs). However, the electrostatic field would be screened by ions. To stabilize colloidal LCs against electrolyte is an unsolved challenge. Here, an effective strategy is proposed to stabilize GO LCs under harsh conditions by association of polyelectrolytes onto GO sheets. Using sodium poly(styrene sulfonate) (PSS) and poly[2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (PMEDSAH), a kind of polyzwitterion, GO LCs were well-maintained in the presence of NaCl (from 0 M to saturated), extreme pH (from 1 to 13), and serum. Moreover, PSS- or PMEDSAH-coated chemically reduced GO (rGO) also showed stability against electrolyte.
在纳米科学中，胶体的稳定化对于其基础研究和实际应用具有重要意义。静电排斥稳定的各向异性胶体，如氧化石墨烯（GO），能够形成稳定的液晶（LCs）。然而，静电场会被离子屏蔽。使胶体液晶抵抗电解质仍是一个未解决的挑战。在此，提出了一种有效的策略，通过将聚电解质结合到GO片材上来在苛刻条件下稳定GO液晶。使用聚（苯乙烯磺酸钠）（PSS）和聚[2-（甲基丙烯酰氧基）乙基]二甲基-（3-磺丙基）氢氧化铵（PMEDSAH），一种聚两性离子，在存在NaCl（从0 M到饱和）、极端pH（从1到13）和血清的情况下，GO液晶得到了很好的维持。此外，涂覆有PSS或PMEDSAH的化学还原氧化石墨烯（rGO）也表现出对电解质的稳定性。
