Resilient Polymer Nanocomposites for Type II Thermal Interface Materials

Thermal interface materials (TIMs) in electronics are typically used between the heat source and heat sink to enhance heat dissipation. TIMs are continuously exposed to harsh conditions such as temperature cycling, mechanical stress, humidity, vibration, and shock, which can lead to failure and hinder efficient thermal conduction. Both thermal and mechanical properties are equally important for electronic reliability and performance. However, mechanical properties are often overlooked in the literature compared to thermal properties. This study emphasizes the fabrication of TIMs based on thermoplastic elastomer (TPE) nanocomposites with mechanical robustness and sufficient thermal conductivity. The form factor of the TIM is Type II, an elastomeric thermal pad. Mechanical robustness in the TIMs is achieved through triblock copolymers of polystyrene-block-polyisoprene-block-polystyrene (SIS). Thermal conductivity of these robust films is enhanced by incorporating functionalized 2D hexagonal boron nitride (BN) nanoplatelets. Above 20 vol.% BN, both in plane and cross plane thermal conductivities decrease. Additionally, the incorporation of the nanoplatelets increases surface roughness, elastic modulus, and mechanical hysteresis. We observe that an increase in nanofiller content negatively impacts mechanical performance without necessarily improving thermal conductivity. Thus, understanding the balance of mechanical and thermal performance is critical for optimization. The results obtained through this research can offer valuable insights for designing elastomeric thermal pads.