Issue 38, 2015

The observation of a conductivity threshold on the electrorheological effect of p-phenylenediamine oxidized with p-benzoquinone

Abstract

p-Phenylenediamine was oxidized with p-benzoquinone in the presence of 0.1–5 M methanesulfonic acid (MSA) solutions. The resulting methanesulfonate salts of 2,5-(di-p-phenylenediamine)-1,4-benzoquinone are semiconducting and the particles were further suspended in silicone oil in a weight ratio of 1 : 9 in order to create novel electrorheological fluids. Conductivity measurements using the two-point method along with dielectric spectroscopy were carried out in order to investigate their electrical and dielectric properties, including their silicone-oil suspensions. The higher the concentration of MSA was present during the synthesis, the higher the conductivity was observed. Nevertheless, a certain threshold of the ER effect has been found and a further significant increase in conductivity causes only a slight ER effect enhancement. At an electric field strength of 1.5 kV mm−1, the observed yield stresses read at the low shear rate values were 11.5 Pa, 20.3 Pa, 24.5 Pa, and 28.2 Pa for particles with conductivities 1.5 × 10−12, 8.5 × 10−11, 1.0 × 10−8, and 1.5 × 10−7 S cm−1, respectively. From dielectric spectra, it was observed that the conductivity of the particles determines the relaxation times of their silicone-oil suspensions.

Graphical abstract: The observation of a conductivity threshold on the electrorheological effect of p-phenylenediamine oxidized with p-benzoquinone

Article information

Article type
Paper
Submitted
14 Jul 2015
Accepted
03 Sep 2015
First published
03 Sep 2015
This article is Open Access
Creative Commons BY license

J. Mater. Chem. C, 2015,3, 9973-9980

Author version available

The observation of a conductivity threshold on the electrorheological effect of p-phenylenediamine oxidized with p-benzoquinone

T. Plachy, M. Sedlacik, V. Pavlinek and J. Stejskal, J. Mater. Chem. C, 2015, 3, 9973 DOI: 10.1039/C5TC02119G

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