Direct exfoliation of graphite into graphene in aqueous solutions of amphiphilic peptides
Direct exfoliation of graphite into graphene in aqueous solutions of amphiphilic peptides
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在两亲肽水溶液中将石墨直接剥离成石墨烯
DOI：
10.1039/c5tb02065d
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发表时间：
2016-01-01
影响因子：
7
通讯作者：
Lu, Jian R.
中科院分区：
文献类型：
--
作者：
Cao, Meiwen;Wang, Ningning;Lu, Jian R.
用不同的两亲性多肽在水溶液中直接将石墨烯剥离成层状石墨烯。电荷是决定其石墨剥离效率的重要参数。阴离子分子比阳离子分子更有利，因此效率更高。双子型多肽IleIleCys-CysIleIleIle(I3C-CI3)表现出最高的效率，这可能归因于其特殊的物理化学性质以及与石墨烯片层的相互作用。I3C-Cl3以单体或自组装纳米聚集体的形式吸附在石墨烯表面。这些吸附物种增加了石墨烯/I3C-Cl3复合材料之间的静电斥力和空间斥力。更有趣的是，石墨烯/I3C-CI3复合材料表现出可逆的pH依赖的分散/聚集。这一行为是多肽分子对pH敏感的质子化作用的结果，在用传统表面活性剂剥离的石墨烯分散体中很少发现。此外，还利用石墨烯/I3C-Cl3分散体制备了含有不同纳米结构的自支撑宏观复合膜。这项研究扩大了可用于直接剥离石墨以生产石墨烯薄片的可用试剂的库。使用多肽分子作为石墨烯剥离剂和稳定剂，避免了使用有毒试剂，这可能使制造生物兼容应用的功能复合材料成为可能。
Different amphiphilic peptides were used to mediate the direct exfoliation of graphite into few-layered graphene flakes in aqueous solutions. Charge was found to be an important parameter in determining their graphite exfoliating efficiency. The anionic molecules were more favorable than the cationic ones leading to a higher efficiency. The gemini-type peptide IleIleIleCys-CysIleIleIle (I3C-CI3) exhibited the highest efficiency, which might be attributed to its specific physicochemical properties and interactions with graphene sheets. I3C-CI3 adsorbed onto the graphene surface as either monomers or self-assembled nanoaggregates. These adsorbed species increased both electrostatic and steric repulsions between the graphene/I3C-CI3 composites. More interestingly, the graphene/I3C-CI3 composites showed a reversible pH-dependent dispersion/aggregation. This behavior resulted from the pH-sensitive protonation of the peptide molecules and was rarely found in the graphene dispersions exfoliated by traditional surfactants. Moreover, the graphene/I3C-CI3 dispersion was used to fabricate free-standing macroscopic composite films that contained different nanostructures. The study expands the library of available agents for direct graphite exfoliation to produce graphene sheets. Employing peptide molecules as graphene exfoliating and stabilizing agents avoids the use of toxic reagents, which may allow fabrication of functional composite materials for biocompatible applications.