Tuning the Conductivity of Nanocomposites through Nanoparticle Migration and Interface Crossing in Immiscible Polymer Blends: A Review on Fundamental Understanding

Abstract

This article critically reviews the detailed fundamental understanding of the influence of conductive nanoparticle migration on the localization, and hence, electrical conductivity of immiscible polymer blend nanocomposites. Three types of conductive nanoparticles, namely, spherical, tubular, and platelet, are discussed with respect to their migration and electrical conductivity of obtained nanocomposites. A complete migration process consists of bulk migration within one component, contact with the interface, and penetration to the other component. During processing, the wetting coefficient parameter is the main thermodynamically controlling factor for nanoparticle localization. However, kinetic effects, such as mixing sequence and intensity, viscosity ratio, size and shape of the nanoparticles, and mixing time, can play a substantial role in determining the final locations of nanoparticles. Moreover, the rate of migration varies with the surface chemistry of the nanoparticles. It has been reported that nanoparticles in a more viscous phase move slower compared with a low viscous phase. Furthermore, nanoparticles having high aspect ratios and surface polarities compatible with the other component migrating faster. It is established that immiscible polymer blend nanocomposites with a “double percolation” structure having higher conductivity with nanoparticles are localized at the interface of the co‐continuous blends.

Effect of nanofillers characteristics and their selective localization on morphology development and rheological properties of melt‐processed polylactide/poly(butylene adipate‐co‐terephthalate) blend composites

“…Importantly, several key factors, such as the nanoparticle/polymer interaction, surface tension, viscosity ratio, molecular weight, blending sequence, mixing time, and type of mixer, play an important role in the localization of nanoparticles inside immiscible blends. [ 28,42,47,54,55 ] For instance, our previous work revealed that more CNTs could migrate to the PLA/PVDF interface when an internal mixer was used than when the nanocomposites were prepared using a twin‐screw extruder. [ 42 ] Another study showed that nanoclay particles are dispersed through the entire PLA/PBAT blend when they are processed through a twin‐screw extruder.…”

The Influence of the Blend Ratio in PA6/PA66/MWCNT Blend Composites on the Electrical and Thermal Properties

“…The resulting blend-nanocomposite properties depend on the miscibility of the polymers and the localization of the MWCNTs. Many studies are focused on the preparation of nanocomposite blends with a co-continuous morphology and selective localization of nanotubes in one component or at the interface [26,27,28,29,30,31], since the phenomenon of double percolation can be used in such systems [26,27,28,29,30,32].…”

Design of sandwich structure conductive polypropylene/styrene‐butadiene‐styrene triblock copolymer/carbon black composites with inherent morphological tunability

“…Compared with the traditional conductive materials, conductive polymer composites (CPCs) with low cost, ease of processing, tunable conductivity and lightweight have been attracting increasing interest in a wide variety of fields (such as anti-static materials, electromagnetic shielding materials, positive temperature coefficient materials, sensor, conductor, and so on). [1][2][3][4][5][6][7][8][9] CPCs are prepared by dispersing conductive fillers in the insulating polymer matrix to form conductive networks. The percolation theory indicates that the resistivity of CPCs decreases several orders of magnitude when the addition of filler arrives at a critical content called the percolation threshold.…”