National Aeronautics and Space Administration

Glenn Research Center

Gecko inspired work from Case: Dry adhesive holds in extreme cold, strengthens in extreme heat

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10:00 am-12:00 pm

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Controlled Growth and Functionalization of Three-Dimensional Carbon Nanomaterials for Multifunctional Applications
Tuesday, February 27th at 10:00 a.m.
Bldg. 106 Room 202

Liming Dai
Center of Advanced Science and Engineering for Carbon (Case4Carbon)
Departments of Macromolecular Science and Engineering,
Case Western Reserve University, Cleveland, Ohio, 44106, USA

Carbon nanomaterials, including 1D carbon nanotubes (CNTs) and 2D single-atomic layer graphene, have been demonstrated to show superior thermal, electrical, and mechanical properties. Due to their dimensionally confined structures, however, these 1D and 2D nanomaterials exhibit strong direction-dependent thermal and electrical transport properties with extremely low out-of-plane conductivities. In many practical applications, however, it is highly desirable to have carbon nanomaterials with good conductivities for electricity/heat in all the three dimensions.

We have previously developed simple pyrolytic methods for large-scale production of vertically-aligned carbon nanotube arrays. The well-aligned structure provides unique advantages for not only an efficient device construction but also controlled functionalization. The controlled functionalization of aligned carbon nanotubes is particularly attractive, as it allows bulk/surface characteristics of the aligned carbon nanotubes to be tuned while their alignment structure can be largely retained. We have also reported the preferential synthesis of semiconducting vertically-aligned single-walled carbon nanotubes. Recently, we have further demonstrated that metal-free, nitrogen-doped aligned carbon nanotubes exhibited high electrocatalytic activities for energy conversion and storage, and that hierarchically-structured aligned carbon nanotube arrays with a straight body segment and a curly entangled top showed almost ten-times stronger shear adhesion force than that of a real gecko foot but still can be easily lifted off in the normal direction when desired. More recently, we have exploited various approaches to 3D pillared carbon architectures, consisting of parallel graphene layers supported by vertically-aligned carbon nanotubes in between, which possess desirable out-of-plane transport and mechanical properties while maintaining the excellent properties of their building blocks. These 3D carbon nanomaterials are promising for numerous applications.

In this talk, I will summarize some of our rational concepts for the controlled growth and functionalization of 3D carbon nanomaterials for multifunctional materials and device applications (e.g., gecko-foot-mimetic dry adhesives, integrated energy devices), along with an overview on the recent developments in this exciting field.

*Please contact Tiffany Williams (LMN/3-3232) if you would like to arrange a time to meet with Dr. Liming Dai.*