The nature of the bond is a dominant factor in determining the thermal
transport across interfaces. In this paper, we study the role of the hydrogen bond in
thermal transport across interfaces between hard and soft materials with different
surface functionalizations around room temperature using molecular dynamics
simulations. Gold (Au) is studied as the hard material, and four different types of
organic liquids with different polarizations, including hexane (C5H11CH3), hexanamine (C6H13NH2), hexanol (C6H13OH), and hexanoic acid (C5H11COOH), are
used to represent the soft materials. To study the hydrogen bonds at the Au/organic
liquid interface, three types of thiol-terminated self-assembled monolayer (SAM)
molecules, including 1-hexanethiol [HS(CH2)5CH3], 6-mercapto-1-hexanol [HS-
(CH2)6OH], and 6-mercaptohexanoic acid [HS(CH2)5COOH], are used to
functionalize the Au surface. These SAM molecules form hydrogen bonds with the
studied organic liquids with varying strengths, which are found to significantly improve
efficient interfacial thermal transport. Detailed analyses on the molecular-level details
reveal that such efficient thermal transport originates from the collaborative effects of the electrostatic and van der Waals portions
in the hydrogen bonds. It is found that stronger hydrogen bonds will pull the organic molecules closer to the interface. This
shorter intermolecular distance leads to increased interatomic forces across the interfaces, which result in larger interfacial heat
flux and thus higher thermal conductance. These results can provide important insight into the design of hard/soft materials or
structures for a wide range of applications