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An inseparable part of ionic actuator characterization is a set of adequate measurement devices. Due to significant limitations of available commercial systems, in-house setups are often employed. The main objective of this work was to develop a software solution for running isotonic and isometric experiments on a hardware setup consisting of a potentiostat, a linear displacement actuator, a force sensor, and a voltmeter for measuring the force signal. A set of functions, hardware drivers, and measurement automation algorithms were developed in the National Instruments LabVIEW 2015 system. The result is a software called isotonic (displacement) and isometric (force) electro-chemo-measurement software (IIECMS), that enables the user to control isotonic and isometric experiments over a single compact graphical user interface. The linear ionic actuators chosen as sample systems included different materials with different force and displacement characteristics, namely free-standing polypyrrole films doped with dodecylbenzene sulfonate (PPy/DBS) and multiwall carbon nanotube/carbide-derived carbon (MWCNT-CDC) fibers. The developed software was thoroughly tested with numerous test samples of linear ionic actuators, meaning over 200 h of experimenting time where over 90% of the time the software handled the experiment process autonomously. The uncertainty of isotonic measurements was estimated to be 0.6 µm (0.06%). With the integrated correction algorithms, samples with as low as 0 dB signal-to-noise ratio (SNR) can be adequately described.

Either as salts or room temperature ionic liquids, fluorinated anion-based electrolytes have been a common choice for ionic electroactive polymer actuators, both linear and bending. In the present work, propylene carbonate solutions of four electrolytes of the three hugely popular anions—triflouromethanesulfonate, bis(trifluoromethane)sulfonimide, and hexafluorophosphate were compared and evaluated in polypyrrole linear actuators. The actuation direction, the characteristics—performance relations influence the behavior of the actuators. Isotonic Electro-chemo-mechanical deformation (ECMD) measurements were performed to study the response of the PPy/DBS samples. The highest strain for pristine PPy/DBS linear actuators was found in range of 21% for LiTFSI, while TBAPF6 had the least cation involvement, suggesting the potential for application in durable and controllable actuators. Interesting cation effects on the actuation of the same anions (CF3SO3−) were also observed.

Conducting polymers such as polypyrrole (PPy) can be deposited on various substrates to obtain conductive electroactive coatings. While electrochemical coatings are generally considered to be more effective, chemical coatings are more industrially suitable, especially on complex substrates. In this work, we aimed to explore the electro‐chemo‐mechanical response of conductive fiber scaffolds (CFS) prepared by coating PPy (chemically) on glucose‐gelatin nanofibre scaffolds. Electroactivity was readily observed in both aqueous and propylene carbonate solutions of lithium bis(trifluoromethanesulfonyl)imide, with mainly anion activity in both cases. A higher actuation response was achieved in the aqueous solutions with strain in the range of 1.2% and stress in the range of 3 kPa. Under both cyclic voltammetry and square wave potential steps driving, stable actuation for over 100 cycles was maintained. In addition to actuation, the CFS samples exhibited concurrent sensory properties, in sensing current densities and mechanical load. The PPy‐coated CFS material functioning as both an actuator and a sensor is envisaged to have potential applications in smart materials, soft robotics or e‐skin. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48533.

Here we present the synthesis and characterization of two new conducting materials having a high electro-chemo-mechanical activity for possible applications as artificial muscles or soft smart actuators in biomimetic structures. Glucose-gelatin nanofiber scaffolds (CFS) were coated with polypyrrole (PPy) first by chemical polymerization followed by electrochemical polymerization doped with dodecylbenzensulfonate (DBS-) forming CFS-PPy/ DBS films, or with trifluoromethanesulfonate (CF 3 SO 3-, TF) giving CFS-PPy/TF films. The composition, electronic and ionic conductivity of the materials were determined using different techniques. The electro-chemo-mechanical characterization of the films was carried out by cyclic voltammetry and square wave potential steps in bis(trifluoromethane)sulfonimide lithium solutions of propylene carbonate (LiTFSI-PC). Linear actuation of the CFS-PPy/DBS material exhibited 20% of strain variation with a stress of 0.14 MPa, rather similar to skeletal muscles. After 1000 cycles, the creeping effect was as low as 0,2% having a good long-term stability showing a strain variation per cycle of-1.8% (after 1000 cycles). Those material properties are excellent for future technological applications as artificial muscles, batteries, smart membranes, and so on.