Nano-level lubricant tuning improves material for electronic devices and surface coatings

14-Feb-2017 - USA

molybdenum disulfide (MoS₂), which is ubiquitously used as a solid lubricant, has recently been shown to have a two-dimensional (2D) form that is similar to graphene. But, when thinned down to less than a nanometer thick, MoS₂ demonstrates properties with great promise as a functional material for electronic devices and surface coatings.

Researchers at the University of Illinois at Urbana-Champaign have developed a new approach to dynamically tune the micro- and nano-scale roughness of atomically thin MoS₂, and consequently the appropriate degree of hydrophobicity for various potential MoS₂-based applications.

"The knowledge of how new materials interact with water is a fundamental," explained SungWoo Nam, an assistant professor of mechanical science and engineering at Illinois. "Whereas the wettability of its more famous cousin, graphene, has been substantially investigated, that of atomically thin MoS₂--in particular atomically thin MoS₂ with micro- and nano-scale roughness--has remained relatively unexplored despite its strong potential for fundamental research and device applications. Notably, systematic study of how hierarchical microscale and nanoscale roughness of MoS₂ influence its wettability has been lacking in the scientific community."

"This work will provide a new approach to dynamically tune the micro- and nano-scale roughness of atomically thin MoS₂ and consequently the appropriate degree of hydrophobicity for various potential MoS₂-based applications," stated Jonghyun Choi, a mechanical engineering graduate student and first author of the article. "These include waterproof electronic devices with superhydrophobicity with water contact angle greater than 150 degrees. It may also be useful for medical applications with reduced hydrophobicity (WCA less than 100 degrees) for effective contact with biological substances. "

According to the authors, this study, expands the toolkit to allow tunable wettability of 2D materials, many of which are just beginning to be discovered.

"When deformed and patterned to produce micro- and nano-scale structures, MoS₂ shows promise as a functional material for hydrogen evolution catalysis systems, electrodes for alkali metal-ion batteries, and field-emission arrays," Nam added. "The results should also contribute to future MoS₂-based applications, such as tunable wettability coatings for desalination and hydrogen evolution."

Original publication

Jonghyun Choi, Jihun Mun, Michael Cai Wang, Ali Ashraf, Sang-Woo Kang, and SungWoo Nam; "Hierarchical, Dual-Scale Structures of Atomically Thin MoS2 for Tunable Wetting"; Nano Letters; 2017

https://www.chemeurope.com/en/news/161868/nano-level-lubricant-tuning-improves-material-for-electronic-devices-and-surface-coatings.html

Original publication

Jonghyun Choi, Jihun Mun, Michael Cai Wang, Ali Ashraf, Sang-Woo Kang, and SungWoo Nam; "Hierarchical, Dual-Scale Structures of Atomically Thin MoS2 for Tunable Wetting"; Nano Letters; 2017

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