arxiv: 2604.13741 · v1 · submitted 2026-04-15 · ⚛️ physics.app-ph · cond-mat.mtrl-sci

Recognition: unknown

Universal thermometry of solid-liquid interfacial thermal conductance

Tao Chen , Puqing Jiang

Authors on Pith no claims yet

Pith reviewed 2026-05-10 12:06 UTC · model grok-4.3

classification ⚛️ physics.app-ph cond-mat.mtrl-sci

keywords interfacial thermal conductancesquare-pulsed thermometrysolid-liquid interfacesnanoscale liquid film thicknessheat transportvibrational mismatchwettability

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The pith

A square-pulsed thermometry method quantifies thermal conductance at arbitrary solid-liquid interfaces.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper develops a square-pulsed heating method to measure how well heat crosses solid-liquid interfaces in a universal way. It works for any combination of solids and liquids and also finds the thickness of thin liquid layers on the surface. When tested, aluminum with water conducts heat at 50-55 million watts per square meter per degree, glass with water at 9.9, and silicon with water at 5.7. The same method applied to silicone oil shows even lower values, especially with plastic surfaces. These measurements help explain the role of material properties like vibration matching and wetting in controlling interface heat transfer.

Core claim

The authors claim that their universal broadband square-pulsed thermometry method enables simultaneous quantification of interfacial thermal conductance (ITC) across a wide range of arbitrary solid-liquid interfaces, while also providing accurate measurements of nanoscale liquid-film thickness. Validation on Al-water yields ITC values in the range of 50-55 MW m^{-2} K^{-1}, consistent with prior studies. The technique reveals markedly lower ITCs for glass-water (9.9 MW m^{-2} K^{-1}) and Si-water (5.7 MW m^{-2} K^{-1}), and extends to Al-silicone oil (~10 MW m^{-2} K^{-1}) and PMMA-silicone oil (~0.4 MW m^{-2} K^{-1}). Comparisons with acoustic/diffuse mismatch models and molecular dynamics,

What carries the argument

The broadband square-pulsed thermometry method, which applies square-pulse heating to isolate interfacial conductance from bulk and film effects for arbitrary interfaces without material-specific corrections.

Load-bearing premise

The heat transfer model for square-pulse heating accurately isolates interfacial conductance from bulk and film effects for arbitrary interfaces without unaccounted optical artifacts.

What would settle it

Repeating the Al-water measurement with an independent method such as time-domain thermoreflectance and obtaining a value outside the 50-55 MW m^{-2} K^{-1} range would challenge the isolation of conductance in the model.

Figures

Figures reproduced from arXiv: 2604.13741 by Puqing Jiang, Tao Chen.

**Figure 2.** Figure 2: Experimental configuration and results for thermal transport across the water/Si interface: (a) schematic of the sample with the water layer confined between glass/Al and Si substrates; (b, d, f) SPS signals measured at 0.5, 1, and 9 MHz, respectively, with a laser spot radius 𝑟" = 16 𝜇m; (c, e, g) corresponding sensitivity curves of the four fitting parameters at each frequency. Analysis of sensitivity cu… view at source ↗

**Figure 3.** Figure 3: (a) Measured interfacial thermal conductance (G) for Al-water, glass-water, Si-water, Alsilicone oil, and PMMA-silicone oil. The aqueous interfaces are benchmarked against literature data from TDTR (Ge et al.8 ), bi-directional differential 3ω (Jiao et al.33), and steady-state ASTM D5470 measurements (Yu et al.34), as well as molecular dynamics (MD) simulations of solid-water interfaces (Huang et al.35: A… view at source ↗

read the original abstract

Solid-liquid interfacial thermal conductance (ITC) critically influences heat transport in microfluidic, electronic, and energy systems, yet most optical thermometry techniques are limited to specific metal-liquid interfaces. In this work, we introduce a universal broadband square-pulsed thermometry method that enables simultaneous quantification of ITC across a wide range of arbitrary solid-liquid interfaces, while also providing accurate measurements of nanoscale liquid-film thickness. To validate the method, we applied it to Al-water interfaces, yielding ITC values in the range of 50-55 MW m^(-2) K^(-1), consistent with prior studies. The technique also reveals markedly lower ITCs for glass-water (9.9 MW m^(-2) K^(-1)) and Si-water (5.7 MW m^(-2) K^(-1)), and further measurements on Al-silicone oil (~10 MW m^(-2) K^(-1)) and PMMA-silicone oil (~0.4 MW m^(-2) K^(-1)) extend the validation to highly viscous nonpolar liquids and polymer-liquid interfaces. These results highlight the capability of the method to capture thermal transport differences across diverse solid-liquid combinations. Further comparisons with acoustic/diffuse mismatch models and molecular dynamics simulations, together with theoretical analysis, highlight the influence of vibrational mismatch, wettability, and surface condition on interfacial thermal transport. This broadly applicable technique enables rapid, quantitative characterization of solid-liquid interfacial thermal transport, with broad implications for interfacial heat transfer science and technology.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Desk Editor's Note private letter to a colleague

The paper gives a square-pulsed thermometry method that works on non-metal solids and viscous liquids, with results that match known Al-water values, but the simultaneous fit for conductance and film thickness needs checking for optical and parameter issues.

read the letter

The paper's key advance is a broadband square-pulsed thermometry method that measures solid-liquid interfacial thermal conductance on a wider set of materials than before. It works for non-metals like glass, silicon, and PMMA, and with viscous liquids like silicone oil, while also estimating the liquid film thickness. They validate it first on aluminum-water, recovering 50-55 MW per square meter per kelvin, which lines up with published values. Then they report lower conductances for glass-water and silicon-water, and very low ones for the oil interfaces. Comparisons to acoustic and diffuse mismatch models plus simulations tie the differences to vibrational mismatch and surface properties. This is useful because prior optical techniques were stuck on metal-liquid pairs. The new setup gives a single method for quick characterization across engineering-relevant combinations. The potential weakness is in the underlying heat transfer model. Simultaneous extraction of conductance and nanoscale thickness from one transient can suffer from parameter correlation if the optical absorption or heat spreading varies with the solid. The reported values are plausible, but without detailed error analysis or tests for optical artifacts on low-absorbing interfaces, the accuracy for arbitrary cases is not fully demonstrated. Readers working on heat management in microfluidics or electronics would get practical data from the comparisons. It is worth a serious referee's time to check the model assumptions and reproducibility. I recommend sending this to peer review rather than desk rejecting it.

Referee Report

3 major / 2 minor

Summary. The manuscript introduces a universal broadband square-pulsed thermometry technique that uses transient heating to simultaneously extract solid-liquid interfacial thermal conductance (ITC) and nanoscale liquid-film thickness for arbitrary interfaces. Validation includes Al-water (ITC 50-55 MW m^{-2} K^{-1}, consistent with literature), glass-water (9.9 MW m^{-2} K^{-1}), Si-water (5.7 MW m^{-2} K^{-1}), Al-silicone oil (~10 MW m^{-2} K^{-1}), and PMMA-silicone oil (~0.4 MW m^{-2} K^{-1}), plus comparisons to acoustic/diffuse mismatch models, molecular dynamics simulations, and analysis of vibrational mismatch, wettability, and surface effects.

Significance. If the extraction method proves robust, the work would be significant for enabling rapid ITC characterization beyond metal-liquid systems that dominate prior optical thermometry, with direct relevance to microfluidics, electronics cooling, and energy devices. Simultaneous film-thickness measurement is a useful addition, and the reported values align with expectations for the tested interfaces. However, the claimed universality hinges on the heat-transfer model's ability to separate parameters without interface-specific biases.

major comments (3)

[Methods / theoretical model] Heat-transfer model (square-pulse transient analysis): the claim that a single broadband pulse yields unique, unbiased values for both ITC and film thickness across arbitrary solids (including low-absorbing glass, Si, PMMA) requires explicit demonstration that the two parameters are not degenerate. Variations in optical penetration depth, reflectivity, or lateral spreading can produce correlated shifts in the fitted ITC and thickness; the manuscript should include sensitivity analysis, covariance matrices from the fits, or multiple initial-condition tests to rule this out, particularly for the PMMA-oil result of ~0.4 MW m^{-2} K^{-1}.
[Results / validation experiments] Results for non-metallic interfaces (glass-water, Si-water, PMMA-oil): while values are plausible, the absence of reported error bars, fit statistics, or controls for optical artifacts and surface condition undermines the universality assertion. The model must be shown to isolate ITC without interface-specific corrections; otherwise the comparative claims (e.g., markedly lower ITC for glass/Si vs. Al) rest on unverified assumptions.
[Discussion / theoretical analysis] Comparison with acoustic/diffuse mismatch models and MD simulations: the discussion of vibrational mismatch and wettability is interesting, but without propagating experimental uncertainties from the ITC fits into the model comparisons, it is unclear whether the observed differences are statistically significant or could arise from fitting biases.

minor comments (2)

[Abstract] Abstract: define 'broadband' explicitly (e.g., frequency content of the square pulse) and cite the specific prior Al-water studies whose values are stated to be consistent.
[Figures] Figure clarity: ensure all transient curves include error bars or shaded uncertainty regions and label the fitting windows used for ITC/thickness extraction.

Simulated Author's Rebuttal

3 responses · 0 unresolved

We thank the referee for their careful reading and constructive comments, which have helped us identify areas where the robustness of our method can be more explicitly demonstrated. We address each major comment below and outline revisions that will be incorporated into the manuscript.

read point-by-point responses

Referee: [Methods / theoretical model] Heat-transfer model (square-pulse transient analysis): the claim that a single broadband pulse yields unique, unbiased values for both ITC and film thickness across arbitrary solids (including low-absorbing glass, Si, PMMA) requires explicit demonstration that the two parameters are not degenerate. Variations in optical penetration depth, reflectivity, or lateral spreading can produce correlated shifts in the fitted ITC and thickness; the manuscript should include sensitivity analysis, covariance matrices from the fits, or multiple initial-condition tests to rule this out, particularly for the PMMA-oil result of ~0.4 MW m^{-2} K^{-1}.

Authors: We agree that explicit verification of parameter uniqueness is essential to support the claimed universality. The broadband square-pulse excitation was designed to provide independent information on the fast interfacial resistance and slower film-thickness diffusion timescales, but the original manuscript did not include a dedicated degeneracy analysis. In the revised version we will add a new subsection with (i) a sensitivity study varying initial guesses over orders of magnitude and demonstrating convergence to the same ITC and thickness values, (ii) the covariance matrix extracted from the nonlinear least-squares fits for each interface (including PMMA-oil), and (iii) a brief discussion of how optical penetration depth and lateral heat spreading are accounted for in the model. These additions will directly address the concern for low-absorbing substrates. revision: yes
Referee: [Results / validation experiments] Results for non-metallic interfaces (glass-water, Si-water, PMMA-oil): while values are plausible, the absence of reported error bars, fit statistics, or controls for optical artifacts and surface condition undermines the universality assertion. The model must be shown to isolate ITC without interface-specific corrections; otherwise the comparative claims (e.g., markedly lower ITC for glass/Si vs. Al) rest on unverified assumptions.

Authors: We acknowledge that the presentation of uncertainties and experimental controls can be strengthened. The quoted ITC values were obtained from global fits to the transient thermoreflectance traces; we will add the corresponding standard errors (derived from the fit covariance) as error bars on all reported values and in the figures. We will also include a supplementary note describing (a) control measurements on bare solid surfaces to quantify optical-artifact contributions and (b) the standardized surface-cleaning and liquid-film deposition protocols used to minimize variability. These revisions will make clear that the model extracts ITC without ad-hoc, interface-specific corrections beyond the general multilayer heat-transfer framework. revision: yes
Referee: [Discussion / theoretical analysis] Comparison with acoustic/diffuse mismatch models and MD simulations: the discussion of vibrational mismatch and wettability is interesting, but without propagating experimental uncertainties from the ITC fits into the model comparisons, it is unclear whether the observed differences are statistically significant or could arise from fitting biases.

Authors: We concur that uncertainty propagation is required for a statistically meaningful comparison. In the revised manuscript we will overlay the experimental ITC values (with their fit-derived uncertainties) on the AMM, DMM, and MD predictions and will explicitly discuss whether the observed differences (e.g., lower conductance for glass/Si versus Al) remain significant once experimental error bars are included. We will also add a short paragraph addressing possible fitting biases and how the broadband excitation reduces their impact relative to single-frequency methods. revision: yes

Circularity Check

0 steps flagged

No circularity: experimental method validated against independent literature

full rationale

The paper introduces a square-pulsed thermometry technique for measuring solid-liquid ITC and film thickness, then reports experimental values (e.g., Al-water 50-55 MW m^{-2} K^{-1}) that are explicitly compared to prior independent studies, acoustic/diffuse mismatch models, and MD simulations. No load-bearing step reduces a claimed result to a fitted parameter or self-citation by construction; the extraction relies on a heat-transfer model whose outputs are tested against external benchmarks rather than defined by them. This is the standard case of a self-contained experimental paper with no circular derivation chain.

Axiom & Free-Parameter Ledger

1 free parameters · 1 axioms · 0 invented entities

The central claim depends on the validity of a standard heat conduction model applied to pulsed heating and on experimental controls for optical signals; no new physical entities are introduced.

free parameters (1)

Interfacial thermal conductance
Extracted by fitting observed temperature decay to the pulsed heating model for each interface tested.

axioms (1)

domain assumption Temperature evolution under square-pulse illumination can be modeled to separate interfacial resistance from other thermal paths.
Fundamental to extracting ITC from the measured signals.

pith-pipeline@v0.9.0 · 5569 in / 1178 out tokens · 49652 ms · 2026-05-10T12:06:38.427161+00:00 · methodology

discussion (0)

Reference graph

Works this paper leans on

4 extracted references · 1 canonical work pages

[1]

(a) Measured interfacial thermal conductance (G) for Al-water, glass-water, Si-water, Al-silicone oil, and PMMA-silicone oil. The aqueous interfaces are benchmarked against literature data from TDTR (Ge et al.8), bi-directional differential 3ω (Jiao et al.33), and steady-state ASTM D5470 measurements (Yu et al.34), as well as molecular dynamics (MD) simul...

2024
[2]

14 Tao Chen, Shangzhi Song, Yang Shen, Kexin Zhang, and Puqing Jiang, International Communications in Heat and Mass Transfer 158, 107849 (2024)

13 Guangfan Meng, Jiao Chen, Wenlong Bao, and Zhaoliang Wang, Heat Mass Transfer 59 (2), 203 (2023). 14 Tao Chen, Shangzhi Song, Yang Shen, Kexin Zhang, and Puqing Jiang, International Communications in Heat and Mass Transfer 158, 107849 (2024). 15 Shangzhi Song, Tao Chen, and Puqing Jiang, J. Appl. Phys. 137 (5), 055101 (2025). 16 Tao Chen and Puqing Jia...

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[3]

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work page arXiv 2024
[4]

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2012