Biomimetic polypyrrole based all three-in-one triple layer sensing actuators exchanging cations

Abstract

Simultaneous actuation and sensing properties of a triple layer actuator interchanging cations are presented for the first time. Thick polypyrrole (pPy)/dodecylbenzenesulfonate (DBS) films (36 mm) were electrogenerated on stainless steel electrodes. Sensing characteristics of pPy-DBS/tape/pPy-DBS triple layer artificial muscle were studied as a function of electrolyte concentration, temperature and driving current using lithium perchlorate (LiClO 4 ) aqueous solution as electrolyte. The chronopotentiometric responses were studied by applying consecutive square waves of currents to produce angular movements of AE45 by the free end of the triple layer. The evolution of the muscle potential (anode film versus cathode film) during current flow is a function of the studied chemical and physical variables. The electrical energy consumed to describe a constant angle is a linear function of the working temperature or of the driving electrical current, and a double logarithmic function of the electrolyte concentration. Those are the sensing functions. The cation exchanging bending triple layer actuator senses the working conditions. Similar sensing functions were described in the literature for devices interchanging anions. Irrespective of the reaction mechanism, a single electrochemo-mechanical device comprised of two reactive polymer electrodes (oxidation film and reduction film) works simultaneously as both sensor and actuator (self-sensing actuators). These are the general sensing properties of dense and biomimetic reactive gels of conducting polymers. Thus, any reactive device based on the same type of materials and reactions (batteries, smart windows, actuators, electron-ion transducers) is expected to sense surrounding conditions, as biological organs do.

Biomimetic Conducting Polymers: Synthesis, Materials, Properties, Functions, and Devices

“…42 12.1.1 Dual Sensing-Actuators: Sensing and Tactile Artificial Muscles. Equation (17) states that the evolution of the muscle potential during actuation is affected, as obtained empirically 26,108,121,122,124,[129][130][131][132][133] by the electrolyte concentration, the temperature, any mechanical variable acting on the volume variation (trailed weights, obstacles, pressure) and frequency. Driven by a constant current, the potential of the muscle (and the consumed electrical energy) during the description of the same angular amplitude every time, that is, from Figs.…”

“…11D, c and c ). 121,123,124 As conclusion, artificial muscles are electrical motors driven by reaction 2 under control of the Faraday's laws.…”

Simultaneous Smart Actuating-Sensing Devices Based on Conducting Polymers

“…Under flow of a constant current (constant reaction rate) the achieved potential is lower when a variable which favours the electrochemical reaction increases. This is the case for temperature (Garcia-Cordova et al, 2011;Ismail et al, 2011;Otero & Cortes, 2003b;Valero Conzuelo et al, 2010; or electrolyte concentration GarciaCordova et al, 2011;Otero & Cortes, 2003b;Otero et al, 2007b;Valero Conzuelo et al, 2010). On the other hand, the potential shifts to higher values when a variable makes the reaction harder: the muscle moves larger masses (Garcia-Cordova et al, 2011;Otero et al, 2007b;Valero Conzuelo et al, 2010) or moves the mass faster by applying now rising currents (Garcia-Cordova et al, 2011;Ismail et al, 2011;Valero et al, 2011).…”

“…The triple layer was immersed in an electrolyte allowing the current flow. One of the conducting polymer films acts as the anode while the second film acts as the cathode (Garcia-Cordova et al, 2011;John et al, 2008;Yao et al, 2008). But using this configuration it is also possible to obtain movement outside a liquid electrolyte media using an ionic conducting membrane to separate the two films of conducting polymers.…”

Properties and Customization of Sensor Materials for Biomedical Applications

“…However, thus far, such sensors suffer from poor sensitivity and high LODs (144,189,192,193). PANi deposited on plastic substrates by means of ink-jet printing was used to detect pH changes both potentiometrically and spectrophotometrically (192), but the selectivity factor hampered their use in real-sample scenarios (192).…”