Surfactant assisted tuning of electrical conductivity, electromagnetic interference shielding effectiveness, wetting properties of poly(lactic acid)-expanded graphite-magnetite nanocube hybrid bio-nanocomposites

The study aimed at demonstrating polyvinylpyrrolidone (PVP) amount is critical for tuning the electrical conductivity and electromagnetic interference shielding effectiveness (EMI SE) of poly(lactic acid)-expanded graphite (ExGr)-magnetite (Fe3O4) nanocube hybrid nanocomposites. An optimum loading of PVP (1 wt.%) was found to disperse the nanofillers resulting in enhanced electrical conductivity and EMI SE in X-band dominated by the absorption mechanism. The electrical conductivity enhancement in hybrid nanocomposites was not only attributed to the network formation between fillers but also onto the thickness of the coated surfactant layer. The interjunction capacitance and real part of relative permittivity of the hybrid nanocomposites were also enhanced at 1 wt.% PVP addition in comparison to 0 wt.% and 2 wt.% surfactant loading. The water contact angle was found to depend on the surface roughness of the film, which varied with both PVP and ExGr loadings. These PLA based hybrid nanocomposite materials can be used as microwave absorbing material. [Display omitted] •The electrical conductivity of PLA/ExGr, PLA/ExGr/magnetite hybrid nanocomposites increases with appropriate PVP loading.•The effect of surfactant loading is reflected in ac conductance and impedance of PLA/ExGr/magnetite hybrid nanocomposites.•Incorporation of magnetite nanocubes in PLA/ExGr nanocomposites enhances EMI SE dominated by absorption process in X-band.•Wettability can be tuned by the loading of magnetite nanocubes in PLA/ExGr nanocomposites.•Synthesis of magnetite nanocubes by simple method. The study aimed at demonstrating polyvinylpyrrolidone (PVP) amount is critical for tuning electrical conductivity and electromagnetic interference shielding effectiveness (EMI SE) of poly(lactic acid)-expanded graphite (ExGr)-magnetite (Fe3O4) nanocube hybrid nanocomposites. An optimum loading of PVP (1 wt.%) was found to disperse the nanofillers resulting in enhanced electrical conductivity and EMI SE in the X-band dominated by the absorption mechanism. The electrical conductivity enhancement in hybrid nanocomposites was not only attributed to the network formation between fillers but also to the thickness of the coated surfactant layer. The inter-junction capacitance and real part of relative permittivity of the hybrid nanocomposites were also enhanced at 1 wt.% PVP addition in comparison to 0 wt.% and 2 wt.% surfactant loading. The water contact angle was found to depend on the surface rough