Capillary-Force-Assisted Self-Assembly (CAS) of Highly Ordered and Anisotropic Graphene-Based Thin Films

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• 作者：Rachel Tkacz ; Rudolf Oldenbourg ; Alex Fulcher ; Morteza Miansari ; Mainak Majumder
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：January 9, 2014
• 年：2014
• 卷：118
• 期：1
• 页码：259-267
• 全文大小：469K
• ISSN：1932-7455

文摘

We report capillary-force-assisted self-assembly (CAS) as a method for preparation of thin films of chemically reduced graphene oxide (rGO) with unidirectional organization of rGO sheets. The films were initiated at the contact line of the air鈥搇iquid鈥搒olid interface and form directly on solid substrates dipped in an isotropic colloidal suspension of rGO. Assisted by capillary forces at the contact line, the suspension undergoes an isotropic-to-anisotropic phase transition and becomes aligned with the film growth direction as the contact line moves across the substrate surface. We determined the degree of order in rGO films and assemblies by birefringence and diattenuation imaging. The slow axis of the rGO platelets within the CAS films displayed a narrow angular distribution (卤3掳) within a film area of 1 mm², resulting in the highest possible order parameter (S) of 1 with 8-fold enhancement of electrical conductivity compared to films formed by traditional techniques such as filtration. Our straightforward film fabrication technique is scalable to produce large areas of films, and by controlling the rates of convective to diffusive mass transport, films with varying degree of order can be produced.