Sang In Eom

Proposal of a peristaltic micropump using dielectric elastomer actuators fabricated by MEMS technology

A peristaltic micropump using dielectric elastomer (DE) actuators is proposed and developed. The peristaltic micropump is designed so that diaphragm-type DE actuators are placed serially on a microchannel and volume changes due to diaphragm-type DE actuators can transfer fluid and pressure. In this report, we propose a novel MEMS process that enables us to place multiple DE actuators on the microchannel. In order to fabricate a DE actuator using a MEMS technology, ultraviolet (UV) curable materials for both compliant electrodes and DE were selected. Poly(3, 4- ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) was used for compliant electrodes. PEDOT:PSS is a polymer mixture of two ionomers and a conductive, transparent polymer. As a DE material, polydimethylsiloxane (PDMS) was used. PDMS is a silicon-based organic polymer and is widely used for the DE. In this research, both PEDOT:PSS and DE modified to have an UV curable property were used. In order to verify the proposed fabrication process, we developed a diaphragm-type DE actuator using UV curable PEDOT:PSS and PDMS. The DE actuator is a disk shape with 10 mm diameter and 0.8 mm thickness. A diaphragm-type DE actuator was fabricated in the order of (1) a bottom cover, (2) a bottom compliant electrode, (3) a DE, (4) a top compliant electrode, and (5) a top cover by using UV curable material patterning. In the driving experiment, we measured an out-of-plane displacement of 55 μm when 2.5 kV was applied to the DE actuator.

Development of a MEMS-based electro-rheological microfinger system with an alternating pressure source

This paper presents a novel MEMS-based electro-rheological (ER) microfinger system with an alternating pressure source for multiple microactuator systems. Based on rectifying alternating flow by the ER microvalves, the ER microfinger system enables half number and small size of supply and return pipes, which is suitable for multiple microactuator systems. The MEMS-based finger part was realized by newly developed PDMS micromolding process featuring high-aspect-ratio and three-dimensional structures. This is the first time demonstration of bi-directional, large-displacement of 1.1 mm and high-speed (rise time of 1.1 s) bending motion of the fabricated 1.6-mm long ER microfinger.