Thermal transport in silver-coated polymer sphere composites by the bidirectional 3 ω method

• Main Authors: Chávez-Ángel, E. (Author), He, J. (Author), Kristiansen, H. (Author), Sandell, S. (Author), Wang, T. (Author), Zhang, Z. (Author)
• Format: Article
• Language: English
• Published: American Institute of Physics Inc. 2022
• Subjects: Adhesives; Biological samples; Coated polymers; Composite films; Conductive adhesive; Epoxy-based; Metallics; Mono-disperse; Polymer spheres; Polymethyl methacrylates; Silver; Silver pastes; Silver thin films; Thermal conductivity; Thermal transport; Volume fraction
• Online Access: View Fulltext in Publisher

 The bidirectional 3 ω method is an electrothermal technique that is commonly used to obtain the thermal conductivity of materials such as liquids, biological samples, and pastes. In this work, an epoxy-based adhesive was filled with monodisperse 10 μm polymethyl methacrylate spheres coated with silver thin films (AgPS), such that a metallic network that dominated the thermal transport was formed through the composite. The bidirectional 3 ω method was used to obtain the thermal conductivity of the conductive adhesive at different volume fractions of AgPS. For 50 vol.% AgPS, corresponding to 3.4 vol.% silver, the thermal conductivity was 2.03 ± 0.21 W m-1 K-1. The results show that the thermal conductivity is strongly correlated with the AgPS volume fraction, while maintaining a volume fraction of silver far below the commercial silver paste, which has typical filler fractions of 40 vol.% silver. The results of this work were compared to thermal measurements of the same material by other techniques, and advantages and disadvantages of the methods were finally discussed. © 2022 Author(s).