Thermal Transport and Functional Properties of Conformal Coatings for Automotive Electronics

This study presents a comparative analysis of the structural, electrical, optical, thermal, and mechanical properties of the conformal coatings used for electronic protection: acrylic coating, polyurethane coating, and silicone-modified acrylic coating. The chemical structure of the coatings was analyzed by Fourier-transform infrared (FTIR) spectroscopy, their electrical insulation properties were evaluated by electrical resistance measurements, and their optical properties were investigated by UV–Vis–NIR spectrophotometry over the 200–2500 nm range. The effects of coating type and actual coating thickness on heat transport and relative hardness were also evaluated. FTIR analysis revealed differences in the chemical structure of the investigated materials and confirmed the presence of functional groups characteristics of the respective coating types. The highest values electrical resistance recorded for the silicone-modified coating. UV–Vis–NIR measurements showed that both coating type and film thickness affected the reflectance characteristics in the visible and near-infrared ranges. The most favorable heat-transport parameters were obtained for selected acrylic and silicone-modified coating variants, whereas the thermal properties of the polyurethane coatings were more sensitive to changes in layer thickness. The obtained results confirm that the functional properties of conformal coatings depend on both their chemical structure and the actual thickness of the dry film, which should be taken into account when selecting an electrical insulating material when designing insulation in automotive electronic systems.