Graphene-based polymer composite films with enhanced mechanical properties and ultra-high in-plane thermal conductivity

The effect of graphene flake size on the properties of graphene‐based polymer composite films

“…The electrical conductivity increased further after adding 5 wt% and 10 wt% of graphene but with a slower rate due to typical percolation transition behavior for electrical conductivity in conductive polymer composites. 21,30 Consistent with SEM images in Figure 4(d)-(f), large planar flakes (G1 and G2) can be aligned in a plane much better than small round-shape (isotropic) graphene flakes (G3).…”

“…G1-based polymer composites showed the highest value for the in-plane thermal conductivity as shown in Figure 5, which was also reported in our previous papers. 27,30 An ultra-high value of~26 W/m/K was achieved, which again is the highest measured values for in-plane thermal conductivity for PVDF composites. For the same graphene wt%, the in-plane thermal conductivity value was lower for G2 and G3, respectively indicating that the average flake size also has a direct effect on the in-plane thermal conductivity values of the composites.…”

“…For graphene contents higher than 20 wt %, the mechanical properties of the G1 composites are expected to decrease and this observation was presented by the authors in a previous paper. 30 The tensile strength for G1 composites was higher than the tensile strength for G2 and G3 composites with the same graphene loading. For example, for 5 wt % G1, the ultimate strength was~26 MPa, whereas it was 24 MPa and 14.5 MPa for G2 and G3, respectively.…”

“…1,33 Of course, the significant enhancement in tensile strength for G1 composites is also a result of both proper dispersion and adhesion with PVDF-HFP. 30 Inferior response was seen for small flakes in G2 and G3 composites. In G2 and G3 composites, the tensile strength was the highest at 5 wt% and 10 wt%, respectively.…”

High Electromechanical Deformation Based on Structural Beta-Phase Content and Electrostrictive Properties of Electrospun Poly(vinylidene fluoride- hexafluoropropylene) Nanofibers

“…This experience arises from hydrogen bonding between the ionic interactions and unit chain of the polymer with the hydrated Mg–salt and the polar solvent. Various studies have been undertaken to improve the polar β-phase with the incorporation of conductive elements, for example, MWNTs, CNTs, and graphene [15,16,17,18,19,20,21]. The report by Zhou et al [22] demonstrated the β-phase of P(VDF)/graphene composite nanofibers increased with an increase of graphene 0.1 wt %.…”