Enhanced electrical conductivity of sodium polyacrylate encapsulated multi-walled carbon nanotubes

Multi-walled carbon nanotubes (MWNTs) were grafted with poly (acrylic acid) (PAA) forming PAA-g-MWNTs, which were subsequently neutralized with a sodium hydroxide solution resulting in sodium polyacrylate encapsulated MWNTs (PAANa-g-MWNTs). Then PAANa-g-MWNTs were introduced into polyetherimide (PEI) as an electrically conductive additive. The polymer-encapsulated MWNTs could be finely dispersed in the PEI matrix. Moreover, determinations of the electrical conductivity and electrochemical impedance spectra (EIS) of the nanocomposites indicated that the electrical conductive percolation threshold of PAANa-g-MWNTs in PEI was decreased obviously over that of pristine MWNTs, and partially because of the improved dispersion of the conductive filler, partially because of the joint efforts of the moderate ionic conductivity induced by PAANa with the electronic conductivity by MWNTs in the polymer matrix.

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► PAANa-g-MWNTs were introduced into PEI as an electrically conductive additive.
► The percolation threshold was decreased from 4% of MWNTs to 1.75% of PAANa-g-MWNTs.
► The enhanced conductivity came from ionic conducting mechanism induced by PAANa.