Department of Applied Chemistry, Kyungpook National University, Daehak-ro 80, Buk-gu, Daegu 41566, Republic of Korea.
Department of Biotechnology, The Catholic University of Korea, Bucheon-si, Gyeonggi-do, Republic of Korea.
J Colloid Interface Sci. 2018 Jan 15;510:162-171. doi: 10.1016/j.jcis.2017.09.065. Epub 2017 Sep 18.
In this study, poly(2,2,2-trifluoroethyl methacrylate)-block-poly(4-vinylpyridine) (PTFEMA-b-PVP) was synthesized by stepwise reversible addition-fragmentation chain transfer (RAFT) polymerization for the preparation of graphene by the exfoliation of graphite nanoplatelets (GPs) in supercritical CO (SCCO). Two different block copolymers (low and high molecular weights) were prepared with the same block ratio and used at different concentrations in the SCCO process. The amount of PTFEMA-b-PVP adsorbed on the GPs and the electrical conductivity of the SCCO-treated GP samples were evaluated using thermogravimetric analysis (TGA) and four-point probe method, respectively. All GP samples treated with SCCO were then dispersed in methanol and the dispersion stability was investigated using online turbidity measurements. The concentration and morphology of few-layer graphene stabilized with PTFEMA-b-PVP in the supernatant solution were investigated by gravimetry, scanning electron microscopy, and Raman spectroscopy. Destabilization study of the graphene dispersions revealed that the longer block copolymer exhibited better affinity for graphene, resulting in a higher yield of stable graphene with minimal defects.
在这项研究中，通过逐步可逆加成-断裂链转移（RAFT）聚合合成了聚（2,2,2-三氟乙基甲基丙烯酸酯）-嵌段-聚（4-乙烯基吡啶）（PTFEMA-b-PVP），用于在超临界 CO（SCCO）中通过剥离石墨纳米片（GPs）制备石墨烯。用相同的嵌段比制备了两种不同的嵌段共聚物（低分子量和高分子量），并在 SCCO 过程中以不同的浓度使用。用热重分析（TGA）和四点探针法分别评估了 PTFEMA-b-PVP 在 GPs 上的吸附量和 SCCO 处理的 GP 样品的电导率。然后，将所有用 SCCO 处理的 GP 样品分散在甲醇中，并通过在线浊度测量研究分散体的稳定性。通过重量法、扫描电子显微镜和拉曼光谱研究了用 PTFEMA-b-PVP 稳定的上清液中少层石墨烯的浓度和形态。石墨烯分散体的失稳研究表明，较长的嵌段共聚物对石墨烯具有更好的亲和力，从而以最小的缺陷获得更高产量的稳定石墨烯。
