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Prof. Huiling Duan’s and Prof. Anyuan Cao’s groups collaboratively make progress in carbon nanotube sponge electrocapillary imbibers

Post Time:2016-1-5 13:31:33  点击次数:450

In October 2015,Professor Huiling Duan’s group from College of Engineering, in collaboration with Professor Anyuan Cao’s group from the same college, has made important progress in switchable and compressible carbon nanotube sponge electrocapillary imbibers. The research paper has been published online in Advanced Materials (A Switchable and Compressible Carbon Nanotube Sponge Electrocapillary Imbiber, http://dx.doi.org/10.1002/adma.201502837).

Enabling controllable, efficient fluid transport through predefined nanochannels is an important consideration in developing high performance nanofluidic materials and systems for biological and environmental applications. To this end, finding suitable imbibition materials (imbibers) is critical; many porous media (e.g., silica, polymers, paper, and rock) have exhibited spontaneous imbibition behavior but with limited control on the fluid flow. Our previous work published in Nature Communications (http://www.nature.com/ncomms/2014/140701/ncomms5237/full/ncomms5237.html) utilized the electrocapillary effect to realize controllable imbibition through a conductive media (nanoporous Au) under low operating voltages (e.g., −1 V). However, the hydrophilic nature of Au required preloading of another solvent (cyclohexane) to prevent spontaneous imbibition of water, which consequently restricted the flow rate. In addition, flexible nanofluidic systems with tailored pore sizes are highly desired for many applications.

The present work published in Advanced Materials has demonstrated a high-performance CNT sponge-based nanoporous imbiber utilizing its 3D conductive network and highly porous structure. Carbon nanotube sponges are light-weight, conductive, highly porous and flexible; an integration of these properties is suitable for constructing high-performance electrocapillary imbibers. Water imbibition into the sponges could be initiated at low potentials with tunable uptaking rates and switched on and off reversibly with fast imbibition rate. The CVD-fabricated CNT sponges may be integrated into capillary systems as accurately controllable capillary pumps. Moreover, it is possible to build deformable imbibition media with desired pore sizes since the bulk sponges can be compressed to different degrees while maintaining the imbibition function. In the future, these CNT sponges could be shaped and integrated into a variety of micro- and nanofluidic systems for biological, environmental, and other applications.

Copper wire-supported carbon nanotube sponges (A) and electric-switchable control of imbibition in as-grown and compressed sponges (B)

The first author of the paper is Dr. Yahui Xue from Professor Duan’s group. Prof. Duan and Prof. Cao are co-corresponding authors. The above work is supported by National Science Foundation.

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