Water Morphs Into Ice and/or Vapor When Nanoconfined

We all grew up knowing that liquid water turns into vapor if it is boiled to temperatures higher than 100, and turns into ice if it is cold to temperatures lower than 0. Then, we knew from the science class that water maintains its aqueous state in different containers and channels unless either its temperature or pressure changes. Based on these fundamental concepts, all current water applications were developed.

Mohamed Ibrahim Shaat, an assistant professor of mechanical engineering and director of the Mechanics of Nanomaterials and Nanomechanical Systems Laboratory at Abu Dhabi University, with the collaboration of Yongmei Zheng, a professor of chemistry and director of the Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education at Beihang University, demonstrated that water - at ambient conditions - can easily morph into different phases when it is confined into nanotubes. Thus, water would turn into ice or vapor not only by changing its temperature and/or pressure but also by severely confining it. It was revealed that severely confined water exhibits a multiphase structure where it forms vapor, ice and liquid (side-by-side) inside the nanotube. Dr. Shaat demonstrated these findings by developing a new hybrid continuum-molecular mechanics (HCMM); a new concept of mechanics that can capture surface wettability and confinement effects on the fluid mechanics. Indeed, these new findings improve our current understanding of water desalination systems and help in the development of nanofluidics for various engineering and medical applications. This novel work has been published in Scientific Reports – Nature (“Fluidity and phase transitions of water in hydrophobic and hydrophilic nanotubes”).

This work is part of Dr. Shaat’s research on the Mechanics of Nanomaterials and Nanomechanical Systems. His research aims to the implementation of nanomaterials for commercial and public benefits. He leads an international research group that develops and theorizes new methods and techniques of engineering and tailoring advanced materials and mechanical systems that would achieve optimized performance of current aerospace, medical, automotive, and defense applications.

Reference

Mohamed Shaat, Yongmei Zheng “Fluidity and phase transitions of water in hydrophobic and hydrophilic nanotubes” (2019) 9:5689.