A High-Modulus Electroactive Polymer Acting as a Robust Ionomer for Ionic Micro-Actuators
- PDF / 214,251 Bytes
- 5 Pages / 432 x 648 pts Page_size
- 69 Downloads / 286 Views
A High-Modulus Electroactive Polymer Acting as a Robust Ionomer for Ionic MicroActuators Gokhan Hatipoglu1, Yang Liu1, Ran Zhao1, Mitra Yoonessi2,3, Dean M. Tigelaar2,3, Srinivas Tadigadapa1, and Q. M. Zhang1 1 Department of Electrical Engineering, Pennsylvania State University, University Park, PA 16802, USA 2 Ohio Aerospace Institute, Cleveland OH, USA 3 NASA Glenn Research Center, Cleveland, OH 44135, USA
ABSTRACT A high modulus, sulfonated polymer synthesized from one-to-one ratio 4,6-bis(4hydroxyphenyl)-N, N-diphenyl-1,3,5-triazin-2-amine and 4,4′-biphenol with bis(4-fluorophenyl) sulfone (DPA-PS:BP) is exploited as an ionomer for micro-ionic actuators. A unique and attractive feature of the ionomer is that it can contain high amounts of ionic liquid (IL) as an electrolyte while maintaining a high elastic modulus (i.e 600 MPa for 150 wt% uptake), which is more than one order of magnitude higher than the state-of-the-art of ionomers with working electrolytes. Such a high modulus makes it possible for the ionomer to be fabricated into microactuators with high uptake of ILs and low operation voltage ( < 4 V), in various free standing forms with ion milling techniques, which are attractive for MEMS applications. As an initial demonstration of a DPA-PS:BP based ionic micro-actuator, a cantilever (200 μm x 33 μm x 5 μm) is manufactured by Focused Ion Beam (FIB) and characterized. Under the voltage of 1.6 V, the bending actuator exhibits an intrinsic strain from the active ionomer of 1.1% and a corresponding blocking force of 27 μN. INTRODUCTION Ionic polymer-metal composites (IPMC) are a subclass of ionic electro-active polymers (iEAP), which have a basic structure of an electrolyte containing polymer membrane such as NafionTM, FlemionTM, and AquivionTM ionomers sandwiched between two electrodes. The high percentage of IL uptake in the polymer membranes improves the ionic conductivity, which may also improve the actuator response speed and actuation level due to higher concentration of ions [1]. Nevertheless, high uptakes of electrolyte (usually > 40 vol %) cause dramatic reduction of elastic modulus of the ionomers, eventually leading to the polymer membrane lose its robustness, which is critical for many MEMS applications where thin polymer membranes are employed [2]. In this study, in-house synthesized [3] highly aromatic sulfonated poly(arylene ether sulfone)s with 1,3,5-s-triazin ionomer, DPA-PS:BP (1:1), was utilized as the ionomer membrane actuator, which has the ability of high IL uptake to generate high strain at relatively low voltage while maintaining a high elastic modulus.
235
EXPERIMENTAL DPA-PS:BP was synthesized by polycondensation reaction of 4,6-bis(4-hydroxyphenyl)N,N-diphenyl-1,3,5-triazin-2-amine and 4,4′-biphenol with bis(4-fluorophenyl) sulfone in one to one ratio. The chemical structure is shown in figure 1.
Figure 1. The chemical structure of DPA-PS:BP (1:1) Thin DPA-PS:BP membranes with different IL uptakes were prepared using a solution cast method. In this solution cast process, DPA-P
Data Loading...
