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Engineered Ionic Polymer Metal Composites (eIPMCs) represent the next generation of IPMCs, soft electro-chemo-mechanically coupled smart materials used as actuators and sensors. Recent studies indicate that eIPMC sensors, featuring unique microstructures at the interface between the ionic polymer membrane and the electrode, exhibit enhanced electrochemical behavior and sensitivity under compression, as compared to traditional IPMCs. However, a complete and experimentally-validated model of how eIPMCs behave under dynamic compression loads is currently missing. In this paper, we develop an analytical model for eIPMC sensors, elucidating the role of the engineered interface, modeled as a separate material layer with unique mechanical and electrochemical properties. Theoretical predictions focus on the mechanical-to-electrochemical transduction response under dynamic compressive loads. Experimental verification is conducted on conventional IPMC and novel eIPMC samples fabricated using the polymer abrading technique. Electrochemical impedance spectroscopy is performed to study the effect of the engineered interface on the electrochemical properties. Open-circuit (OC) voltage and short-circuit (SC) current are measured under external compressive loads in different loading scenarios to demonstrate sensing performance. Results show good qualitative agreement between experimental trends and model predictions. Experiments over the frequency range 1-18 Hz demonstrate an increase of 220%-290% in open-circuit voltage and 17%-166% in SC current sensitivity for eIPMCs over IPMCs. 

Abstract Endoluminal devices are indispensable in medical procedures in the natural lumina of the body, such as the circulatory system and gastrointestinal tract. In current clinical practice, there is a need for increased control and capabilities of endoluminal devices with less discomfort and risk to the patient. This paper describes the detailed modeling and experimental validation of a magneto-electroactive endoluminal soft (MEESo) robot concept that combines magnetic and electroactive polymer (EAP) actuation to improve the utility of the device. The proposed capsule-like device comprises two permanent magnets with alternating polarity connected by a soft, low-power ionic polymer-metal composite (IPMC) EAP body. A detailed model of the MEESo robot is developed to explore quantitatively the effects of dual magneto-electroactive actuation on the robot’s performance. It is shown that the robot’s gait is enhanced, during the magnetically-driven gait cycle, with IPMC body deformation. The concept is further validated by creating a physical prototype MEESo robot. Experimental results show that the robot’s performance increases up to 68% compared to no IPMC body actuation. These results strongly suggest that integrating EAP into the magnetically-driven system extends the efficacy for traversing tract environments. 

Abstract This paper focuses on the modeling and development of engineered ionic polymer-metal composite (eIPMC) sensors for applications such as postural and tactile measurement in mechatronics/robotics-assisted finger rehabilitation therapy. Specifically, to tailor the sensitivity of the device, eIPMCs, fabricated using a polymer-surface abrading technique, are utilized as the sensing element. An enhanced chemoelectromechanical model is developed that captures the effect of the abrading process on the multiphysics sensing behavior under different loading conditions. The fabricated sensors are characterized using scanning electron microscopy imaging and cyclic voltammetry and chronoamperometry. Results show significant improvement in the electrochemical properties, including charge storage, double layer capacitance, and surface conductance, compared to the control samples. Finally, prototype postural-tactile finger sensors composed of different eIPMC variants are created and their performance validated under postural and tactile experiments. The tailored eIPMC sensors show increased open-circuit voltage response compared to control IPMCs, with 7.7- and 4.7-times larger peak-to-peak bending response under postural changes, as well as a 3.2-times more sensitive response under compression during tactile loading, demonstrating the feasibility of eIPMC sensors. 

The soft and compliant nature of ionic polymer-metal composite (IPMC) sensors has recently been investigated for various applications in soft robotic and mechatronic devices. Recent results of physics-based chemoelectromechanical modeling suggest that IPMC asymmetric surface roughening may enhance the sensitivity under compression. This paper presents initial experimental results on IPMC compression sensors fabricated with varying degrees of asymmetric surface roughness. The roughness is created through a simple mechanical sanding process on the base polymer material, referred to as "polymer abrading technique'", followed by traditional electroless plating to create electrodes. Sample sensors are characterized by measuring the voltage response under different compressive loads. The results show consistently increased sensor sensitivity of the asymmetrically roughened IPMCs versus a control sample. Sensitivity increases non-monotonically with rougher electrode surfaces, where maximum sensitivity of about 0.0433 mV/kPa is achieved with sensor electrodes with 53-74~micrometer abrasions. More variability is also observed through augmented electrode roughness, suggesting greater flexibility for IPMC sensor design. These results align with predictions from the existing physics-based chemoelectromechanical model. 

Abstract In this paper, we examine the development of tailored 3D-structured (engineered) polymer-metal interfaces to create enhanced ionic polymer-metal composite (eIPMC) sensors towards soft, self-powered, high sensitivity strain sensor applications. First, a physics-based chemoelectromechanical model is developed to predict the sensor behavior of eIPMCs by incorporating structure microfeature effects in the mechanical response of the material. The model incorporates electrode surface properties, such as microscale feature thickness, size and spacing, to help define the mechanical response and transport characteristics of the polymer-electrode interface. Second, two novel approaches are described to create functional samples of eIPMC sensors using fused deposition manufacturing and inkjet printing technologies. Sample eIPMC sensors are fabricated for experimental characterization. Finally, experimental results are provided to show superior performance in the sensing capabilities compared to traditional sensors fabricated from sheet-form material. The results also validate important predictive aspects of the proposed minimal model. 

Abstract This paper introduces a magneto-electroactive endoluminal soft (MEESo) robot concept, which could enable new classes of catheters, tethered capsule endoscopes, and other mesoscale soft robots designed to navigate the natural lumens of the human body for a variety of medical applications. The MEESo locomotion mechanism combines magnetic propulsion with body deformation created by an ionic polymer-metal composite (IPMC) electroactive polymer. A detailed explanation of the MEESo concept is provided, including experimentally validated models and simulated magneto-electroactive actuation results demonstrating the locomotive benefits of incorporating an IPMC compared to magnetic actuation alone. 

This paper presents the design, modeling, analysis, and experimental validation of an inductive resonant wireless power transfer (WPT) system to power a micro aerial vehicle (MAV). Using WPT, in general, enables longer flight times, virtually eliminates the need for batteries, and minimizes down time for recharging or replacing batteries. The proposed WPT system consists of a transmit coil, which can either be fixed to ground or placed on a mobile platform, and a receive coil carried by the MAV. The details of the WPT circuit design are presented. A power-transfer model is developed for the two-coil system, where the model is used to select suitable coil geometries to maximize the power received by the MAV for hovering. Analysis, simulation, and experimental results are presented to demonstrate the effectiveness of the WPT circuitry. Finally, a wirelessly powered MAV that hovers above the transmit coil is demonstrated in a laboratory setting.