Highly thermally conductive PVDF-based composites with well-dispersed carbon nanotubes/graphene-Ag 3D interconnected frame via electrostatic self-assembly

Abstract

Polyvinylidene fluoride (PVDF) is a thermoplastic polymer known for its superior chemical and thermal stability and good mechanical properties. However, the application of polymers in heat transfer is limited by their inherent poor thermal conductivity (λ). This study uses electrostatic self-assembly between negatively charged Graphene-Silver (GNs-Ag) and positively charged cetyltrimethylammonium bromide (CTAB)-functionalized multiwall carbon nanotubes (fMWCNTs) to construct a unique three-dimensional (3D) structure in PVDF. AgNPs are uniformly loaded on graphene nanosheets, and the well-dispersed fMWCNTs act as bridges connecting adjacent AgNPs and GNs, forming a more efficient heat transfer pathway, thereby obtaining polymer nanocomposites with higher λ. The λ of GNs-Ag/fMWCNTs/PVDF composites reaches 9.24 W/(m·K) with 25 wt% of GNs-Ag/fMWCNTs fillers, which is 3495 % higher than that of pure PVDF. Additionally, the mechanical properties and electrical conductivity and electromagnetic interference shielding effectiveness of the GNs-Ag/fMWCNTs/PVDF composites are also markedly enhanced.