Highly efficient thermal conductivity of polydimethylsiloxane composites via introducing “Line-Plane”-like hetero-structured fillers

Graphite oxide (GO) and cetyltrimethylammonium bromide (CTAB) modified multi-walled carbon nanotubes (m-MWCNTs) are utilized to fabricate “Line-Plane”-like hetero-structured thermally conductive GO@MWCNTs fillers by electrostatic self-assembly, which are then introduced into polydimethylsiloxane (PDMS) to fabricate thermally conductive GO@MWCNTs/PDMS composites. When the mass ratio of GO to m-MWCNTs is 2:1, GO@MWCNTs fillers have optimal morphologies and thermal conductivity contribution. When the mass fraction of GO@MWCNTs is 20 wt%, the thermal conductivity coefficient (λ) of GO@MWCNTs/PDMS composites reaches 2.10 W/(m·K), 950% higher than that of pure PDMS (0.20 W/(m·K)), which is also superior to the λ of MWCNTs/PDMS (0.68 W/(m·K)), GO/PDMS (1.59 W/(m·K)) and (GO/MWCNTs)/PDMS (1.28 W/(m·K)) composites with the same amount of single or hybrid thermally conductive fillers. Meantime, the GO@MWCNTs/PDMS composites also present good thermal conduction stability (average λ after 15 heating-cooling cycles in the temperature of 21 to 100°C is 2.14 W/(m·K)) and thermal stability (heat resistance index is 249.3°C).