Control of Long Range Orientation in Ordered Mesoporous Carbon Thin Films
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University of Akron / OhioLINK
2013
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ndltd-OhioLink-oai-etd.ohiolink.edu-akron13662374042021-08-03T05:22:06Z Control of Long Range Orientation in Ordered Mesoporous Carbon Thin Films Xue, Jiachen Polymers Ordered mesoporous carbons are appealing for many application areas, where their function and performance depend critically on structure. Thus, alignment of these mesopores by scalable methods is of notable interest. Cooperative self-assembly provides a facile route to fabrication of ordered mesoporous materials. Heating causes ordering and crosslinking of the carbon precursor (phenolic resin); the relative kinetics of these two processes can lead to complications. Typically, silicon wafers have served as the support for thin films; quartz presents a physicochemically similar surface, but we find significant improvements in ordering of mesoporous carbon films prepared on quartz relative to silicon wafers. The role of annealing temperature on the porosity, pore size distribution and mechanical properties of the mesoporous films supported on quartz substrates are examined using ellipsometry and wrinkling, respectively. We attribute the significant differences between the films processed on silicon and quartz substrates to their relative thermal conductivities and heat capacities that impact the rate. These results illustrate the subtleties associated with the thermally induced self-assembly process for mesoporous carbons and suggest that support selection will significantly impact the ordered mesostructure.Here, we demonstrate use of a dynamic thermal gradient annealing technique, cold zone annealing (CZA) to obtain 2D cylindrical mesoporous carbon thin films with long range ordered structure and controllable in-plane uniaxial orientation. CZA generates flow in the annealing motion direction from the thermal gradient associated with the CZA to shear-align 2D cylinders along the moving direction. Additionally, the edge of the substrate is approximately 10 °C warmer in the thermal zone, which leads to orthogonal flow from differences in the crosslinking density and can cause cylindrical structure packing transverse to CZA motion direction. By changing the sample translation velocity from 20 ¿m/s to 0.2 ¿m/s, in-plane cylinders can be arranged in different direction relative to moving direction with high uniformity (S > 0.95). Though pyrolysis leads to a slight loss of directionality, mesoporous carbon films can still exhibit an impressive orientational order factor (S = 0.89). This simple technique is a promising continuous fabrication route to obtaining long-range uniaxially aligned mesoporous carbon thin films over large areas without any physical or chemical templating.We achieved striking uniaxially aligned well ordered cylindrical mesoporous carbon through simple route with easy process method. 2013-06-11 English text University of Akron / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=akron1366237404 http://rave.ohiolink.edu/etdc/view?acc_num=akron1366237404 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
| collection |
NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
Polymers |
| spellingShingle |
Polymers Xue, Jiachen Control of Long Range Orientation in Ordered Mesoporous Carbon Thin Films |
| author |
Xue, Jiachen |
| author_facet |
Xue, Jiachen |
| author_sort |
Xue, Jiachen |
| title |
Control of Long Range Orientation in Ordered Mesoporous Carbon Thin Films |
| title_short |
Control of Long Range Orientation in Ordered Mesoporous Carbon Thin Films |
| title_full |
Control of Long Range Orientation in Ordered Mesoporous Carbon Thin Films |
| title_fullStr |
Control of Long Range Orientation in Ordered Mesoporous Carbon Thin Films |
| title_full_unstemmed |
Control of Long Range Orientation in Ordered Mesoporous Carbon Thin Films |
| title_sort |
control of long range orientation in ordered mesoporous carbon thin films |
| publisher |
University of Akron / OhioLINK |
| publishDate |
2013 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=akron1366237404 |
| work_keys_str_mv |
AT xuejiachen controloflongrangeorientationinorderedmesoporouscarbonthinfilms |
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1719418964049657856 |