Extrinsic Wrinkling and Single Exfoliated Sheets of Graphene Oxide in Polymer Composites
Extrinsic Wrinkling and Single Exfoliated Sheets of Graphene Oxide in Polymer Composites
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DOI：
10.1021/acs.chemmater.5b04502
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发表时间：
2016-03-22
影响因子：
8.6
通讯作者：
Clarke, Nigel
中科院分区：
文献类型：
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作者：
Weir, Michael P.;Johnson, David W.;Clarke, Nigel
我们使用反空间散射技术和原子力显微镜研究了氧化石墨烯作为聚苯乙烯和聚甲基丙烯酸甲酯纳米复合材料中的填料的构象。通过减去聚合物散射来估计氧化石墨烯的散射贡献，我们发现表面分形散射在倒易空间中跨越了二十多年的范围，这表明这些材料中的氧化石墨烯在非常宽的长度尺度上是粗糙的，并且意味着广泛的外在起皱和折叠。我们发现，充分剥离的局部平坦氧化石墨烯片在 16 nm 长度尺度的散射中产生交叉，该交叉由来自薄盘或片的质量分形散射的特征主导。我们表明，这些聚合物氧化石墨烯纳米复合材料中的局部氧化石墨烯结构与在相同长度尺度上研究的水溶液中氧化石墨烯的结构相同。我们的结果证实了良好剥离片材的存在，这是在纳米复合材料中实现聚合物和高长径比填料之间高界面面积的关键。
We study the conformation of graphene oxide as the filler in nanocomposites of polystyrene and poly(methyl methacrylate) using inverse-space scattering techniques and atomic force microscopy. By subtracting the polymer scattering to estimate the scattering contribution from the graphene oxide, we discover surface fractal scattering that spans a range of more than two decades in reciprocal space, indicating that the graphene oxide within these materials is rough on a very wide range of length scales and implying extensive extrinsic wrinkling and folding. We discover that well-exfoliated, locally flat sheets of graphene oxide produce a crossover in the scattering at a length scale of 16 nm, which becomes dominated by, the signature of mass fractal scattering from thin disks or sheets. We show that the local graphene oxide structure in these polymer graphene oxide nanocomposites is identical to that of graphene oxide in a water solution studied on the same length scale. Our results confirm the presence of well exfoliated sheets that are key to achieving high interfacial areas between polymers and high aspect ratio filler in nanocomposites.