Combining surface modification of carbon fiber and introduction of phase change capsules to synergistically improve heat dissipation performance of dual-function polymeric composite

Thermally conductive composites are widely employed for heat dissipation of electronic devices, but they suffer from incompatibility between thermally conductive filler and polymeric matrix and lack of a function to relieve thermal shock. Elucidating the relationship between surface modification of thermally conductive filler and interface thermal resistance to optimize thermal conductivity for thermally conductive composite, along with introducing phase change capsules to craft dual-function composite with both heat conduction and storage properties, is expected to address these issues. Herein, we chose polydopamine (PDA)-modified carbon fiber (CF) as a prototype to elucidate relationship between surface modification and interface thermal resistance within polydimethylsiloxane (PDMS)-based composite. Molecular dynamics simulations suggested that the modification with PDA did decrease the interfacial thermal resistance between CF and PDMS, but the loading of PDA needed to be controlled at an appropriate amount. The highest thermal conductivity was achieved by the CF/PDMS composite containing 20 wt% of the optimal PDA-modified CF, which composite was then combined with paraffin@SiO₂ nanocapsules with different mass fractions to craft dual-function composites. The obtained dual-function composites exhibited enhanced thermal conductivity, increased heat storage capacity and decreased hardness with increasing mass fraction of the nanocapsules, all of which changes are positive factors in affecting heat dissipation performance. When loading the nanocapsules at 15 wt%, the obtained dual-function composite achieved much improved heat dissipation performance, accounting for the contributes of both the surface modification with PDA and the introduction of the nanocapsules.