Lee Hoyeon, Choi Ki-In, Choi Jae-Hak, Yoo Jeseung, Seo Young-Soo, Satija Sushil, Koo Jaseung
Neutron Science Center, Korea Atomic Energy Research Institute (KAERI), Daejeon, 34057, Korea.
Department of Organic Materials Engineering, Chungnam Nation University, Daejeon, 34134, Korea.
ACS Appl Nano Mater. 2019;2(7). doi: 10.1021/acsanm.9b00660.
We present a simple and facile approach to creating asymmetrically modified graphene oxide sheets by grafting polymers with different polarities. Single-layered Janus graphene derivatives were prepared by grafting polymers with different polarities at the liquid-gas interface through one step functionalization. This approach allows obtaining free-standing monolayers of Janus graphene oxide sheets for large area, and also controlling the morphology (i.e., wrinkled Janus graphene oxide sheets) by a compression monolayer. A neutron reflectivity technique is used to check the functionalization on each side of the monolayer, and the results are compared with contact angles to determine its amphiphilic nature. The free-standing Janus monolayers become robust after UV-irradiation, and are able to withstand various solvents. Because these robust Janus graphene films can maintain their anisotropic functionalities over time, this technique provides a new strategy for fabricating functional materials that require amphiphilic properties (i.e., oil-water separation membranes and chemical compatibilizers functioning as a 2D surfactant) and different electrical functionalities (i.e., flexible lightweight p-n junction semiconductors and stimuli-driven actuators).
我们提出了一种简单易行的方法，通过接枝不同极性的聚合物来制备不对称修饰的氧化石墨烯片。通过一步功能化在液-气界面接枝不同极性的聚合物，制备了单层的Janus石墨烯衍生物。这种方法能够大面积制备独立的Janus氧化石墨烯片单层，并通过压缩单层来控制其形态（即褶皱的Janus氧化石墨烯片）。利用中子反射技术检查单层每一侧的功能化情况，并将结果与接触角进行比较以确定其两亲性。独立的Janus单层在紫外线照射后变得坚固，能够耐受各种溶剂。由于这些坚固的Janus石墨烯薄膜能够长时间保持其各向异性功能，该技术为制造需要两亲性特性（即油水分离膜和作为二维表面活性剂的化学增容剂）以及不同电学功能（即柔性轻质p-n结半导体和刺激驱动的致动器）的功能材料提供了一种新策略。
