Realizing the Accurate Measurements of Thermal Conductivity over a Wide Range by Scanning Thermal Microscopy Combined with Quantitative Prediction of Thermal Contact Resistance

Abstract

Quantitative thermal performance measurements and thermal management at the micro‐/nano scale are becoming increasingly important as the size of electronic components shrinks. Scanning thermal microscopy (SThM) is an emerging method with high spatial resolution that accurately reflects changes in local thermal signals based on a thermally sensitive probe. However, because of the unclear thermal resistance at the probe‐sample interface, quantitative characterization of thermal conductivity for different kinds of materials still remains limited. In this paper, the heat transfer process considering the thermal contact resistance between the probe and sample surface is analyzed using finite element simulation and thermal resistance network model. On this basis, a mathematical empirical function is developed applicable to a variety of material systems, which depicts the relationship between the thermal conductivity of the sample and the probe temperature. The proposed model is verified by measuring ten materials with a wide thermal conductivity range, and then further validated by two materials with unknown thermal conductivity. In conclusion, this work provides the prospect of achieving quantitative characterization of thermal conductivity over a wide range and further enables the mapping of local thermal conductivity to microstructures or phases of materials.

Bridging a Gap in Thermal Conductivity and Heat Transfer in Hybrid Fibers and Yarns via Polyimide and Silicon Nitride Composites

“…Notably, we measured the temperature gradient on the nanometer scale, and a change as small as 0.5 °C can still be translated to large changes in the thermal conductivity of the material, which we showed in the case of yarns. [43]…”

Unraveling the Impact of Boron Nitride and Silicon Nitride Nanoparticles on Thermoplastic Polyurethane Fibers and Mats for Advanced Heat Management

“…Therefore, controlling the spatial arrangement and orientation of fillers are key parameters to design composites with high thermal conductivity at lower filler loadings. − Electrospinning offers a versatile and scalable approach for producing composite fibers, meshes, and yarns in a single step. − It enables the addition of fillers in high loading percentages and enhances the filler distribution with controllable orientation along the axial direction of polymer fibers. , Moreover, the synergy of the applied electrical field and fillers’ organization during electrospinning improves the alignment of the polymer molecule chains, thereby augmenting the intrinsic thermal conductivity and Young’s modulus of the polymer matrix. − This enhancement in properties expands their applications in yarns, textiles, aerospace engineering, and biomedical devices. − Therefore, understanding the thermal properties of individual micro- and nanofibers is crucial for optimizing material performance and functionality, especially given the unique characteristics that emerge in low-dimensional nanostructures, such as size and temperature dependence of thermal conductivity, and internal phonon boundary and edge scatterings. , Scanning thermal microscopy (SThM) with excellent spatial resolution (<50 nm) and thermal sensitivity (<0.01 °C) stands out among methods for characterizing thermal properties, including materials’ thermal conductivity at the micro- and nanoscale. In this technique, a heated nanothermal tip contacts and scans the surface of the samples at room temperature, capturing and processing thermal feedback signals to derive local temperature distribution on the samples. − …”