Design of superior conductive polymer composite with precisely controlling carbon nanotubes at the interface of a co-continuous polymer blend via a balance of π-π interactions and dipole-dipole interactions

In the current study, we propose an efficient thermodynamic method to precisely control multi-walled carbon nanotubes (MWCNTs) at the interface of a co-continuous PS/PMMA blend to design conductive polymer composites with ultralow percolation threshold. The achievement of the interfacial distribution of MWCNTs is attributed to the balance of π-π interactions between PS and MWCNT surfaces and dipole-dipole interactions between PMMA and carboxyl groups on MWCNT surfaces. It is found that MWCNTs can be well controlled at PS/PMMA interface when carboxyl content on MWCNT surfaces is ca. 0.73 wt%, which can exactly make a balance between π-π interactions and dipole-dipole interactions. Because all the MWCNTs are precisely controlled at the continuous interface to build a percolated conductive pathway, the percolation threshold of this type of conductive polymer composite is lowered from 1.81 wt% (MWCNTs/PS) or 1.46 wt% (MWCNTs/PMMA) to 0.017 wt%, which is an ultralow percolation threshold so far. More importantly, this method can be easily extended to other systems involved with π-π interactions and dipole-dipole interactions.

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