Pyrene‐Functionalized PDMS Dispersant Enables High‐Loading Graphite/PDMS Composites with Enhanced Thermal Conductivity and Processability

Efficient thermal management materials are urgently needed to address the challenges created by rapid miniaturization and increased power density in next‐generation electronics. Polymer nanocomposites are promising candidates for thermal interface materials (TIMs), but their processability is often limited by significant increases in viscosity at the high filler loadings required for effective thermal conductivity. In this study, we demonstrate a versatile approach to produce high‐loading graphite/polydimethylsiloxane (PDMS) composites with superior thermal conductivity and excellent flowability by designing a pyrene‐functionalized polydimethylsiloxane (PyPDMS) dispersant. The PyPDMS serves as an interfacial modifier that modifies strong π‐π interactions with graphite surfaces while maintaining good compatibility with the polydimethylsiloxane (PDMS) matrix. The incorporation of PyPDMS dispersants significantly reduces graphite agglomeration and improves rheological properties, which lowers the viscosity of uncured composites by up to 1.6‐fold compared to those without PyPDMS. This enhancement enables uniform composite fabrication with graphite loadings up to 50 wt.% without compromising processability. The resulting composites maintain flexibility and conformability while exhibiting a 10.57% increase in thermal conductivity compared to composites without PyPDMS. This work presents a practical approach for fabricating high‐loading, processable, thermal interface materials (TIMs) with strong potential for advanced electronic applications that require efficient thermal management.