Zipping dielectric elastomer actuators: characterization, design and modeling

Abstract

We report on miniature dielectric elastomer actuators (DEAs) operating in zipping mode with an analytical model that predicts their behavior. Electrostatic zipping is a well-known mechanism in silicon MEMS to obtain large deformations and forces at lower voltages than for parallel plate electrostatic actuation. We extend this concept to DEAs, which allows us to obtain much larger out-ofplane displacements compared to silicon thanks to the softness of the elastomer membrane. We study experimentally the effect of sidewall angles and elastomer prestretch on 2.3 mm diameter actuators with PDMS membranes. With 15° and 22.5° sidewall angles, the devices zip in a bistable manner down 300 μm to the bottom of the chambers. The highly tunable bistable behavior is controllable by both chamber geometry and membrane parameters. Other specific characteristics of zipping DEAs include well-controlled deflected shape, tunable displacement versus voltage characteristics to virtually any shape, including multi-stable modes, sealing of embedded holes or channels for valving action and the reduction of the operating voltage. These properties make zipping DEAs an excellent candidate for applications such as integrated microfluidics actuators or Braille displays. Abstract. We report on miniature Dielectric Elastomer Actuators (DEAs) operating in zipping mode with an analytical model that predicts their behavior. Electrostatic zipping is a well-known mechanism in silicon MEMS to obtain large deformations and forces at lower voltages than for parallel plate electrostatic actuation. We extend this concept to DEAs, which allows us to obtain much larger out-of-plane displacements compared to silicon thanks to the softness of the elastomer membrane. We study experimentally the e↵ect of sidewalls angle and elastomer prestretch on 2.3 mm diameter actuators with PDMS membranes. With 15 and 22.5 sidewalls angle, the devices zip in a bistable manner down 300 µm to the bottom of the chambers. The highly tunable bistable behavior is controllable by both chamber geometry and membrane parameters. Other specific characteristics of zipping DEAs include well-controlled deflected shape, tunable displacement vs. voltage characteristic to virtually any shape including multi-stable modes, sealing of embedded holes or channels for valving action and reduction of the operating voltage. These properties make zipping DEAs an excellent candidate for applications like integrated microfluidics actuators or Braille displays. Reference

Mechanics of dielectric elastomers: materials, structures, and devices

“…Inspired by octopus suckers, Follador et al (2014) recently designed a novel suction cup using DEs, and this actuator was able to produce up to 6 kPa of pressure in water with a response time of less than 300 ms. DE actuators also have been widely used in microfluidic flow control and large-scale integrated microfluidic chips. These chips consist of arrays of independently controlled pneumatic actuators that can produce pumping or valving action individually (Duncan et al, 2013;Maffli et al, 2013). DE-made actuators can significantly reduce the size of the off-chip components, being a promising candidate to replace the traditional pneumatic powered actuators (Fig.…”

Small, fast, and tough: Shrinking down integrated elastomer transducers

“…When a flow of 200 ml h 1 is forced through the tube by a syringe pump, the valve can control the pressure in the system, from 3. Ma✏i et al have proposed the use of electrostatic zipping to close a micromachined chamber with a soft elastomer membrane, as a way to provide integrated actuation for MLSI chips 17 . Unlike typical DEAs with electrodes on both sides of the membrane, zipping actuators use a single electrode on the dielectric membrane; the cavity above which the membrane is suspended acting as the second electrode.…”

“…Soft and stretchable transducers are key elements in many areas including soft robotics [1][2][3] , haptic devices for touch interaction with humans [4][5][6][7] , tunable optics [8][9][10][11] , energy harvesting [12][13][14] , and microfluidics [15][16][17] . Compared to their rigid counterparts, soft actuators present many unique properties that enable a broad new range of applications.…”

Thin-film dielectric elastomer sensors to measure the contraction force of smooth muscle cells

“…PDMS is also commercially available in variety of Young's moduli (10 2 kPa -10 2 MPa) and can be cast into thin films using a variety of methods [6][7] [8] , hence providing flexibility in design.…”