Tadyszak Krzysztof, Wychowaniec Jacek K, Załęski Karol, Coy Emerson, Majchrzycki Łukasz, Carmieli Raanan
Institute of Molecular Physics, Polish Academy of Sciences, ul. Smoluchowskiego 17, 60-179 Poznań, Poland.
School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland.
Nanomaterials (Basel). 2020 May 18;10(5):957. doi: 10.3390/nano10050957.
The arrangement of two-dimensional graphene oxide sheets has been shown to influence physico-chemical properties of the final bulk structures. In particular, various graphene oxide microfibers remain of high interest in electronic applications due to their wire-like thin shapes and the ease of hydrothermal fabrication. In this research, we induced the internal ordering of graphene oxide flakes during typical hydrothermal fabrication via doping with Calcium ions (~6 wt.%) from the capillaries. The Ca ions allowed for better graphene oxide flake connections formation during the hydrogelation and further modified the magnetic and electric properties of structures compared to previously studied aerogels. Moreover, we observed the unique pseudo-porous fiber structure and flakes connections perpendicular to the long fiber axis. Pulsed electron paramagnetic resonance (EPR) and conductivity measurements confirmed the denser flake ordering compared to previously studied aerogels. These studies ultimately suggest that doping graphene oxide with Ca (or other) ions during hydrothermal methods could be used to better control the internal architecture and thus tune the properties of the formed structures.
二维氧化石墨烯片的排列已被证明会影响最终块状结构的物理化学性质。特别是，各种氧化石墨烯微纤维因其线状的薄形状和水热制备的简便性而在电子应用中备受关注。在本研究中，我们通过从毛细管中掺杂钙离子（约6 wt.%），在典型的水热制备过程中诱导氧化石墨烯薄片的内部有序排列。与先前研究的气凝胶相比，钙离子在水凝胶化过程中有助于形成更好的氧化石墨烯薄片连接，并进一步改变了结构的磁性能和电性能。此外，我们观察到了独特的伪多孔纤维结构以及垂直于长纤维轴的薄片连接。脉冲电子顺磁共振（EPR）和电导率测量结果证实，与先前研究的气凝胶相比，薄片排列更为致密。这些研究最终表明，在水热法中用钙（或其他）离子掺杂氧化石墨烯可用于更好地控制内部结构，从而调节所形成结构的性能。
