Direct Observation of Tunable Thermal Conductance at Solid/porous Crystalline Solid Interfaces Induced by Water Adsorbents

TL;DR

This study demonstrates that water adsorption in porous MOFs can significantly enhance interfacial thermal conductance, offering a new method to control heat transfer at solid/porous interfaces for improved thermal management.

Contribution

It introduces a novel strategy using water adsorption-desorption in MOFs to tunably enhance interfacial thermal conductance, supported by experimental and molecular dynamics simulation results.

Findings

Thermal conductance increased up to 7.1 times using water adsorption.

Dense water channels activate high-frequency lattice vibrations.

Water acts as an additional thermal pathway at the interface.

Abstract

Improving interfacial thermal transport is crucial for heat dissipation in systems. Here, we design a strategy by utilizing the water adsorption-desorption process in porous metal-organic frameworks (MOFs) to tune the interfacial heat transfer. We observe a changeable thermal conductance across the solid/porous MOFs interfaces owing to the dense water channel formed by the adsorbed water molecules in MOFs. Our experimental results show that the interfacial thermal conductance of Au/Cu3(BTC)2 heterointerfaces is increased up to 7.1 folds by this strategy, where Cu3(BTC)2 is a typical porous MOF and usually referred to as HKUST-1. Our molecular dynamics simulations further show that the surface tension of Au layer will cause the adsorbed water molecules in HKUST-1 to gather at the interfacial region. The dense water channel formed at the interfacial region can activate the high-frequency lattice vibrations and act as an additional thermal pathway, and then enhance heat transfer across the interfaces significantly. Our findings provide a new concept for tailoring thermal transport at the solid/porous MOFs heterointerfaces which will largely benefit MOF-related applications.