Extended Data Fig. 5: Material properties and nozzle geometry for HDEA filaments.
From: Rotational multimaterial printing of filaments with subvoxel control
a,b, Dielectric constant of crosslinked dielectric elastomer ink. a, Static dielectric constant measurements. A Randles CPE model was found to fit the data better than a resistor in series with a parallel resistor and capacitor (R-(RC)). b, Dynamic dielectric constant for two specimens. For each specimen, capacitance measurements were performed three times. The plotted data points represent the average dielectric constant computed from the three measurements. For the tested capacitance, low-frequency measurements are expected to be of low accuracy owing to device signal noise. c, Conductivity measurement of carbon-black-based conductive electrode ink. Plot of total resistance, RT, versus gap height, g, using an AC signal frequency of 1 kHz. Linear regression of RT versus g gives a slope, ρ/Ap, of 260,000 ohm m−1 with a standard error of 54,000 ohm m−1, in which ρ is the resistivity of the ink and Ap is the area of the parallel plate. Thus, the resistivity of the ink ρ = 130 ± 30 ohm·m (mean ± standard error) and the conductivity, σ = 1/ρ, is 8 × 10−3 ± 2 × 10−3 S m−1 (mean ± standard error). d,e, Shell–fan-core geometry for RM-3DP of HDEAs. d, Dimensions of nozzle tip overlaid on 3D model of nozzle tip. e, Ideal filament cross-section dimensions for Q* = 1 assume extruded inks extend to half of the wall thickness, dividing the fans from the fan-core and shell. These dimensions were used to calibrate volumetric flow rates before printing, to compute dielectric layer thicknesses and to create filament geometries for finite element analysis simulations.
