Kf 96

The P[VBTMA][PF₆], P[VBTMA][PF₆]-c-PANI, and PANI particles were further washed with water and ethanol, and dried in a vacuum at 100 °C for 48 h. The dry particles were mixed into dimethyl silicone oil (KF-96, Shin-Etsu Chemical Co., Ltd., Tokyo, Japan,) with a kinetic viscosity of 50 cSt at 25 °C with a particle concentration of 27 vol %. The density of particles was measured by a pycnometer method.

The viscosity measurement system consists of a rotational viscometer (DVII+ or DV2T, AMETEK Brookfield) and a suspension in a 300 ml beaker. Apparent viscosities were systematically measured for suspensions with different bead volume fractions, average diameters, shear rates, and liquid matrix viscosities. The shear rate was calculated from the rotational speed and the dimensions of the beaker (inner diameter 73 mm) and spindle (outer diameter 3.2 mm) using the following equation $$\begin{array}{c}\hfill \gamma =\frac{2\omega }{1-{(r_i/r_o)}^2}\end{array}$$ where $\gamma ,\omega ,r_o,r_i$ are the shear rate, angular velocity, inner radius of the outer cylinder (beaker), and radius of the inner cylinder (spindle), respectively. The apparent viscosity of the suspension was calculated from the torque generated in the spindle by rotation. The variation of the apparent viscosity was about 10%. Silicone oil (KF-96, Shin-Etsu Chemical) with viscosities of 0.5, 1.0, 2.0, and 3.0 Pa-s at 24 ${}^{\circ }$ C was used as the low polarity liquid matrix, and the relative permittivity ranged from 2.7 to 2.8, depending on the viscosity. Polyethylene beads (LE-1080, Sumitomo Seika) with average diameters of 9.35, 162.5, 340.0, and 602.5 $\mu m$ were selected as dispersed solid particles, whose sphericity and particle distribution were confirmed to be relevant by using scanning electron microscopy (SEM) imaging. Please refer to^{6 (link)} for more details.