Electrical conductivity of poly(vinyl alcohol)/carbon nanotube multilayer thin films: Influence of sodium polystyrene sulfonate mediated carbon nanotube dispersion
P Rama and S Kummara and R Bandyopadhyaya and AS Panwar and AR Bhattacharyya, POLYMER ENGINEERING AND SCIENCE, 60, 2864-2875 (2020).
This investigation was aimed to enhance the dispersibility of multi- walled carbon nanotubes (MWCNT) using sodium polystyrene sulfonate (Na- PSS) polyelectrolyte. Subsequently, electrically conducting, multi-layer thin films are prepared utilizing layer by layer assembly method with poly(vinyl alcohol) as a host matrix. The highest extent of MWCNT dispersion was observed in MWCNT:Na-PSS ratio of 1:9 (wt/wt), which was estimated from UV-Vis spectroscopic analysis. Zeta potential measurements of Na-PSS modified MWCNT dispersion showed large negative potentials ranging from -52 to -64 mV in the most stable pH range of 4 to 10, suggesting the colloidal stability is due to the long-range repulsive nature of electrostatic interactions from negatively charged sulfonate groups. Complementary molecular dynamics simulations showed that adsorption of Na-PSS imparts a large negative potential to the carbon nanotube surface, which increases with an increase in Na-PSS concentration. The multi-layer thin film of (1:9) MWCNT:Na-PSS exhibited a DC electrical conductivity of 2.96 x 10(2) S/m.
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