Thermal stabilities of polysiloxane fluids modified by metal ions (Ce3+, K+, Zr4+) and their applications in thermal interface materials

Polydimethylsiloxane (PDMS) was modified via high-temperature thermal blending with K⁺, Ce³⁺, and Zr⁴⁺ ions to synthesize metal-incorporated polysiloxane fluids. Structural characterization by ²⁹Si NMR, FT-IR, XPS, and TGA confirmed successful modification. Systematic investigations revealed that the type, content, and blending temperature of metals critically influenced thermal stability and conductivity. Notably, Ce³⁺-modified PDMS exhibited enhanced performance: incorporation of 2 wt% cerium stearate increased intrinsic thermal conductivity to 0.203 W/(m·K) (13.4 % higher than pure PDMS) while significantly reducing dielectric constants from 2.67 to 2.56 and the dielectric loss from 0.0060 to 0.0025 at 1 kHz. Further application studies demonstrated scalable thermal conductivity improvements in alumina-filled composites. Utilizing Ce³⁺-modified PDMS as a matrix and α-trimethylsilyloxy-ω-triethoxysilylethyl terminated PDMS as an alumina surface treatment agent (86 vol% loading), the resultant silicone paste achieved 6.84 W/(m· K), representing a 38.2-fold enhancement over pure PDMS. Analogous formulations with α-dimethylvinylsilyloxy-terminated PDMS as the surface treatment agent attained 6.62 W/(m· K) (a 37.0-fold improvement). Thermal dissipation experiments validated the superior performance of these composites, highlighting their potential for advanced thermal management applications.