Interfacial Thermal Transport of Gold Surfaces Coated with Heterogeneous Monolayers in a Binary Solvent
Year: 2025
Type: article
Abstract: Gold nanoparticles play a key role in thermoplasmonics due to their efficient light-to-heat conversion and their potential for chemical group functionalization. In this study, we investigate the interfacial thermal transport properties of gold surfaces coated with heterogeneous layers in contact with ethanol-water co-solvents commonly used in catalysis. By employing non-equilibrium molecular dynamics simulations, we quantify the thermal transport characteristics of water-ethanol mixtures at relevant experimental concentrations. Our simulations show excellent agreement with experimental Soret coefficients and reveal that ethanol tends to accumulate in the hot regions at experimentally relevant ethanol-water weight fractions. However, the composition of the solvent layers in contact with the hot gold surfaces is primarily influenced by the interfacial interactions between the substrate and solvent. We examine the interfacial thermal conductance of gold surfaces coated with self-assembled monolayers, including hexanethiol (hydrophobic), mercaptohexanol (hydrophilic), and catalytic ligands designed to offer an immobilised form of PdCl$_2$-(diphosphine). Our findings indicate that the preferential adsorption of ethanol (on hydrophobic surfaces) or water (on hydrophilic surfaces) significantly alters the interfacial thermal conductance. These results help explain recent observations in plasmonic sensing experiments. Furthermore, we demonstrate that in heterogeneous surfaces incorporating hydrophobic spacers and catalytic ligands, enhanced heat transport occurs, leading to significant temperature differences among the catalytic ligands, spacers, and the surrounding solvent at nanometer length scales. These insights improve our understanding of thermal and mass transport at catalytic surfaces and will inform the extensive research on thermoplasmonic applications of gold nanomaterials.
Authors: Angad Deshmukh, Chao Zeng, James D. E. T. Wilton-Ely, Fernando Bresme
Institutions: Imperial College London, Thomas Young Centre
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
OpenAlex ID: W4414372122