Bottlebrush Polysiloxane for Designing High-Loading Thermal Interface Materials with Excellent Thermal Conductivity Efficiency and Thixotropy

With the progression of electronic components toward high performance, miniaturization, integration, and increased power, efficient heat dissipation has become essential for maintaining performance and extending service life. To address this significant academic and industrial challenge, thermal interface materials (TIMs) with high thermal conductivity are indispensable. This study presents a bottlebrush polymer with a polymethylvinylsiloxane backbone grafted with octadecanethiol side chains (PMVS-ODT), utilized in conductive PMVS-ODT/Al 2 O 3 composites. These composites demonstrate superior thermal conductivity, improved thixotropy, and low contact thermal resistance ( R c ), outperforming conventional PDMS/Al 2 O 3 composites. The low-viscosity bottlebrush PMVS-ODT can compounded with Al 2 O 3 through a simple and scalable mechanical blending process, enabling Al 2 O 3 loadings as high as 87.8 vol.%. Strong interactions between PMVS-ODT and Al 2 O 3 , along with the compliance and thixotropic properties of PMVS-ODT/79.4 vol.% Al 2 O 3 composites, enhance the thermal conductivity to 8.181 W/(m·K) and reduce the R c to 20.9 mm 2 K/W (20 psi). These results represent increases of 79.9% and decreases of 64.6%, respectively, compared to traditional PDMS/Al 2 O 3 composites. Additionally, significantly enhanced thermal management performance is demonstrated for PMVS-ODT/Al 2 O 3 composites when applied as heat dissipation materials for computer CPUs and LED light modules. This matrix structure design offers an effective strategy for developing high-performance polymer-based TIMs suitable for next-generation advanced electronic applications.