Electrical Impedance of Spin-Coatable Ion Gel Films

Abstract

The electrical properties (capacitance, resistance, and conductivity) of ion gel films were examined as a function of film geometry and temperature by using electrical impedance spectroscopy. Ion gel films, which consist of a triblock copolymer, poly (styrene-b-methyl methacrylate-b-styrene) [SMS], and an ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [EMI][TFSI], were deposited by spin coating from ethyl acetate solution. The thickness (2.2-13.4 μm) and the area (0.01-0.06 cm(2)) of the film sandwiched between two gold electrodes were varied systematically to investigate the relation between the electrical properties and the geometry of the film. The resistance (R) was directly proportional to the thickness and the reciprocal area, as expected, whereas the specific capacitance (C') was insensitive to the film geometry. Importantly, the gel polarization time constants (RC, where C = C' × area) were as small as 2.8 μs for 2.2 μm thick ion gel films. Conductivity and capacitance of the film both increase with increasing temperature, with conductivity following the Vogel-Fulcher-Tamman equation, indicating entropically activated behavior, and capacitance at 10 Hz showing Arrhenius-type activation.

A strain-absorbing design for tissue–machine interfaces using a tunable adhesive gel

“…Figure 2f shows the resistance and capacitance of the various gels; both values depend strongly on the frequency, owing to the low ion mobility in the gels. This trend is also observed in electrical double-layer capacitors 22,23 . The increase in the conductivity at higher frequency is similar to what is noticed in ionic gels 24 .…”

Aerosol Jet Printed, Sub‐2 V Complementary Circuits Constructed from P‐ and N‐Type Electrolyte Gated Transistors

“…An additional attractive feature of electrolyte gate layers is that the low frequency capacitances are independent of the electrolyte layer thickness, which means low voltage circuits can be fabricated easily by printing techniques in which fi lm thicknesses are diffi cult to control with nanometer precision. [ 8 ] EGT operating mechanisms and their advantages for printed electronics have been reviewed recently. [ 9 ] Here, we demonstrate low-voltage complementary circuits based on EGTs fabricated by aerosol jet printing (AJP) of the Adv.…”

Upscaling Organic Electronic Devices

“…[65] The capacitance in a polyelectrolyte EDLC at low frequencies is expected to be practically independent of the thickness of the electrolyte, making EDLOFETS a technology that is well-suited for printed electronics. Indeed, printing techniques such as roll-to-roll or inkjet printing suffer from subpar reproducibility and a large variation in thickness.…”

“…[65] Later on, the use of polyelectrolyte layers of opposite polarities (bipolar membrane) was investigated to produce (ionic) currentrectifying diodes. These bipolar membranes were integrated inside electrochromic displays [Paper III].…”