Electrical Double Percolation of Polybutadiene/Polyethylene Glycol Blends Loaded with Conducting Polymer Nanofibers.

Jun Morita,Shinji Kanehashi,Takeshi Shimomura,Takanori Goto

doi:10.3390/polym12112658

Jun Morita, Shinji Kanehashi + Show 2 more

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https://doi.org/10.3390/polym12112658

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Journal: Polymers	Publication Date: Nov 11, 2020
Citations: 6	License type: CC BY 4.0

Affiliation: Tokyo University of Agriculture and Technology

Abstract

The critical phenomena of double percolation on polybutadiene (PB)/polyethylene glycol (PEG) blends loaded with poly-3-hexylthiophene (P3HT) nanofibers is investigated. P3HT nanofibers are selectively localized in the PB phase of the PB/PEG blend, as observed by scanning force microscopy (SFM). Moreover, double percolation is observed, i.e., the percolation of the PB phase in PB/PEG blends and that of the P3HT nanofibers in the PB phase. The percolation threshold (φcI) and critical exponent (tI) of the percolation of the PB phase in PB/PEG blends are estimated to be 0.57 and 1.3, respectively, indicating that the percolation exhibits two-dimensional properties. For the percolation of P3HT nanofibers in the PB phase, the percolation threshold (φcII) and critical exponent (tII) are estimated to be 0.02 and 1.7, respectively. In this case, the percolation exhibits properties in between two and three dimensions. In addition, we investigated the dimensionality with respect to the carrier transport in the P3HT nanofiber network. From the temperature dependence of the field-effect mobility estimated by field-effect transistor (FET) measurements, the carrier transport was explained by a three-dimensional variable range hopping (VRH) model.

Highlights

Conductive polymer composites (CPC) that comprise immiscible polymer blends and conductive fillers are novel composite materials, featuring advantages of both polymer blends and conductive fillers
Films of PB/polyethylene glycol (PEG) blends loaded with P3HT nanofibers were prepared by spin casting the suspensions at 2000 rpm for 90 s on a substrate, followed by removal of the residual solvent by vacuum drying
To confirm the distribution of P3HT nanofibers in the PB/PEG blended matrix, scanning force microscopy (SFM) observation of the thin-film of the composites was performed by changing the blend ratio of PB/PEG

Summary

Introduction

Conductive polymer composites (CPC) that comprise immiscible polymer blends and conductive fillers are novel composite materials, featuring advantages of both polymer blends and conductive fillers. When loaded in high-density polyethylene (HDPE)/poly(methyl methacrylate) (PMMA) blends, CB was selectively located in the HDPE phase of macro-phase separation, and the HDPE phase was estimated to be the conductive phase. Conducting polymer nanofibers have attracted increasing interest owing to their unique shapes and electrical properties for various applications such as, in molecular wires, organic transistors, and sensors [15,16,17] They are candidates for their use as fillers in CPCs. In particular, nanofibers of regioregular poly(3-hexylthiophene) (P3HT) crystallized from supercooled solutions in adequate solvents exhibit a fine whisker-like structure with a width of 15 nm and length of several μm [18]. By using polymer blends loaded with P3HT nanofibers, we can investigate the multi-scale dimensions of carrier conduction

Materials and Methods

Results and Discussion

Schematic

Conclusions