Lowering of Electrostatic Actuator Driving Voltage and Increasing Generated Force Using Spontaneous Polarization of Ferroelectric Nematic Liquid Crystals

Abstract

Although electrostatic actuators have a simple structure and are lightweight, their range of application is limited because a high applied voltage of more than several kilovolts is required for practical use. Since the force acting between the electrodes of an electrostatic actuator is determined by the electric charge accumulated at the electrode/dielectric interface, the focus is on spontaneous polarization of ferroelectrics to increase the charge. As the ferroelectric material, a nematic liquid crystal material with a spontaneous polarization of 5 μC cm −2 is used. It is demonstrated that a force of 1.3 N is generated at an applied electric field of 0.5 MV m −1 . This force is 1200 times higher than that for standard paraelectric materials with a dielectric constant of ten. Further, the generated force responds linearly to the applied voltage, whereas it is proportional to the square of the applied voltage for paraelectric materials. The actuator function of this ferroelectric is examined using a double-helical coil electrode fabricated using a 3D printer. It can be successfully operated at a voltage of several tens of volts. Under an electric field of 0.25 MV m −1 , a remarkable contraction of 6.3 mm occurs, corresponding to 19% of the original length.

Low-voltage electrohydraulic actuators for untethered robotics

“…We can see that for P(VDF-TrFE-CTFE), the relationship between actuator energy density (force of the actuator) and the applied electric field is nearly linear, whereas for PVDF-HFP and BoPET, it is quadratic. This almost linear force response of PVDF terpolymers to applied voltages has been previously noted in the literature (44)(45)(46). We observed that an actuator made from PVDF-HFP achieves a higher actuator energy density above 280 V μm −1 , owing to a drop of the dielectric energy density of P(VDF-TrFE-CTFE) below the value of PVDF-HFP under high electric fields.…”

Metallization of 3D-Printed UV Photopolymer Structures by the Incorporation of Pd-Decorated Carbon Nanotubes

“…For instance, the metallization involving the nanocomposites is applicable in fabrication of a double-helical coil electrode toward electrostatic actuators reported in a previous study. 50 In conclusion, the Pd-decorated CNT nanocomposites are excellent catalyst and reinforcement of the mechanical strength in metallization of complexstructured 3D multifunctional materials.…”

Rapid, solvent-minimized and sustainable access to various types of ferroelectric-fluid molecules by harnessing mechano-chemical technology

“…Since these discoveries, research into molecular design and synthesis of N F LCs and SmA F LCs has been launched 7,[15][16][17][18][19][20][21][22] toward a clear understanding of the underlying mechanism, 23,24 and development of state-of-the-art materials based on them. 25,26 However, typical synthetic routes of LC materials are through a multistep pathway that entirely rely on the traditional solution chemical (SC) synthesis. As such, the net reaction time (NRT), excluding the purification time, takes a few, or several days to obtain target compounds.…”