Description
Interfacial thermal resistance, commonly expressed through the effective Kapitza length 〖(L〗(k-eff)) , fundamentally constrains heat transport at the nanoscale and sets performance limits for emerging thermal management and energy-conversion technologies. Although surface chemistry and temperature effects have been extensively examined for idealized solid–liquid interfaces, how wettability, nanoscale surface morphology, and temperature jointly regulate interfacial heat transfer in realistic graphene–water systems remains poorly resolved. This lack of understanding obscures the molecular origins of interfacial resistance and limits rational interface design.
Here, we employ non-equilibrium molecular dynamics simulations to systematically quantify the coupled effects of wetting strength, surface morphology, and temperature on heat transfer across graphene–water interfaces. Pristine graphene and two defect-engineered morphologies, including cavity-type and protrusion-type surfaces, are investigated to isolate the role of nanoscale roughness, while wettability is tuned from weakly wetting to strongly hydrophilic regimes and substrate temperature varied between 400 and 1000 K. We show that increasing wettability leads to a pronounced reduction in 〖(L〗(k-eff)) across all morphologies, with the strongest sensitivity occurring in the low-wettability regime. This reduction arises from enhanced liquid layering, strengthened solid–liquid coupling, and more efficient interfacial energy exchange1. At high wettability, 〖(L〗(k-eff)) saturates, marking a transition from contact-limited to transport-limited interfacial heat transfer. Among the studied surfaces, pristine graphene consistently exhibits the lowest 〖(L〗(k-eff)) , reflecting optimal phonon–liquid coupling, whereas cavity and protrusion geometries increase thermal resistance through disrupted interfacial ordering and morphology-induced phonon scattering.
Temperature introduces a non-trivial modulation of interfacial resistance that depends critically on wettability. For weakly wetting interfaces, 〖(L〗(k-eff)) increases sharply with temperature due to diminished liquid structuration and enhanced vibrational mismatch. In contrast, under strong wetting conditions, temperature-induced degradation of interfacial heat transfer is strongly suppressed, underscoring the stabilizing role of robust solid–liquid interactions. By explicitly incorporating 〖(L〗(k-eff)) into a modified Nusselt number, we establish a universal inverse relationship between atomistic interfacial resistance and macroscopic heat-transfer efficiency across all morphologies and wetting states.
These results reveal that interfacial heat transport at graphene–liquid interfaces is governed by a tightly coupled interplay between wettability-controlled liquid ordering, morphology-driven phonon scattering, and temperature-induced interfacial disorder. By directly bridging molecular-scale resistance with continuum heat-transfer metrics, this work thus provides a unified framework and actionable design principles for engineering graphene-based interfaces in high-performance thermal management, energy harvesting, and phase-change technologies.
Reference:
1 S. Debnath, V. Arya, B. Kim, C. Bakli, and S. Chakraborty, “Interplay of topography, wettability, and confinement controls boiling of water over functionalized graphene interfaces,” Energy 333, 137284 (2025).