Force-driven reversible liquid-gas phase transition mediated by elastic nanosponges.

Nomura, Keita; Nishihara, Hirotomo; Yamamoto, Masanori; Gabe, Atsushi; Ito, Masashi; Uchimura, Masanobu; Nishina, Yuta; Tanaka, Hideki et al. · Nat Commun · 2019

basic_science · Level V

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Abstract

Nano-confined spaces in nanoporous materials enable anomalous physicochemical phenomena. While most nanoporous materials including metal-organic frameworks are mechanically hard, graphene-based nanoporous materials possess significant elasticity and behave as nanosponges that enable the force-driven liquid-gas phase transition of guest molecules. In this work, we demonstrate force-driven liquid-gas phase transition mediated by nanosponges, which may be suitable in high-efficiency heat management. Compression and free-expansion of the nanosponge afford cooling upon evaporation and heating upon condensation, respectively, which are opposite to the force-driven solid-solid phase transition in shape-memory metals. The present mechanism can be applied to green refrigerants such as H<sub>2</sub>O and alcohols, and the available latent heat is at least as high as 192 kJ kg<sup>-1</sup>. Cooling systems using such nanosponges can potentially achieve high coefficients of performance by decreasing the Young's modulus of the nanosponge.