Free-Standing Mesoporous Carbon Thin Films with Highly Ordered Pore Architectures for Nanodevices

• Published in: Journal of the American Chemical Society 2011-09, Vol.133 (38), p.15148-15156
• Main Authors: Feng, Dan, Lv, Yingying, Wu, Zhangxiong, Dou, Yuqian, Han, Lu, Sun, Zhenkun, Xia, Yongyao, Zheng, Gengfeng, Zhao, Dongyuan
• Format: Article
• Language: English
• Subjects: Carbon - chemistry; Membranes, Artificial; Nanostructures - chemistry; Particle Size; Porosity; Surface Properties
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja2056227

We report for the first time the synthesis of free-standing mesoporous carbon films with highly ordered pore architecture by a simple coating–etching approach, which have an intact morphology with variable sizes as large as several square centimeters and a controllable thickness of 90 nm to ∼3 μm. The mesoporous carbon films were first synthesized by coating a resol precursors/Pluronic copolymer solution on a preoxidized silicon wafer and forming highly ordered polymeric mesostructures based on organic–organic self-assembly, followed by carbonizing at 600 °C and finally etching of the native oxide layer between the carbon film and the silicon substrate. The mesostructure of this free-standing carbon film is confirmed to be an ordered face-centered orthorhombic Fmmm structure, distorted from the (110) oriented body-centered cubic Im3̅m symmetry. The mesoporosity of the carbon films has been evaluated by nitrogen sorption, which shows a high specific BET surface area of 700 m2/g and large uniform mesopores of ∼4.3 nm. Both mesostructures and pore sizes can be tuned by changing the block copolymer templates or the ratio of resol to template. These free-standing mesoporous carbon films with cracking-free uniform morphology can be transferred or bent on different surfaces, especially with the aid of the soft polymer layer transfer technique, thus allowing for a variety of potential applications in electrochemistry and biomolecule separation. As a proof of concept, an electrochemical supercapacitor device directly made by the mesoporous carbon thin films shows a capacitance of 136 F/g at 0.5 A/g. Moreover, a nanofilter based on the carbon films has shown an excellent size-selective filtration of cytochrome c and bovine serum albumin.