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Ionic polymer-metal composite (IPMC) actuators have considerable potential for a wide range of applications. Although IPMC actuators are widely studied for their electromechanical properties, most studies have been conducted at the ambient conditions. The electromechanical performance of IPMC actuators at higher temperature is still far from understood. In this study, the effect of temperature on the electromechanical behavior (the rate of deformation and curvature) and electrochemical behavior (current flow) of ionic liquid doped IPMC actuators are examined and reported. Both electromechanical and electrochemical studies were conducted in air at temperatures ranging from 25 • C to 90 • C. Electromechanically, the actuators showed lower cationic curvature with increasing temperature up to 70 • C and a slower rate of deformation with increasing temperature up to 50 • C. A faster rate of deformation was recorded at temperatures higher than 50 • C, with a maximum rate at 60 • C. The anionic response showed a lower rate of deformation and a higher anionic curvature with increasing temperatures up to 50 • C with an abrupt increase in the rate of deformation and decrease of curvature at 60 • C. In both cationic and anionic responses, actuators started to lose functionality and show unpredictable performance for temperatures greater than 60 • C, with considerable fluctuations at 70 • C. Electrochemically, the current flow across the actuators was increased gradually with increasing temperature up to 80 • C during the charging and discharging cycles. A sudden increase in current flow was recorded at 90 • C indicating a shorted circuit and actuator failure.

The most rational approach to fabricate soft robotics is the implementation of soft actuators. Conventional soft electromechanical actuators exhibit linear or circular deformation, based on their design. This study presents the use of conjugated polymers, Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) to locally vary ion permeability of the ionic electroactive polymer actuators and manipulate ion motion through means of structural design to realize intrinsic angular deformation. Such angular deformations are closer to biomimetic systems and have potential applications in bio-robotics. Electrochemical studies reveal that the mechanism of actuation is mainly associated with the charging of electric double layer (EDL) capacitors by ion accumulation and the PEDOT:PSS layer’s expansion by ion interchange and penetration. Dependence of actuator deformation on structural design is studied experimentally and conclusions are verified by analytical and finite element method modeling. The results suggest that the ion-material interactions are considerably dominated by the design of the drop-cast PEDOT:PSS on Nafion.

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We have investigated the influence of ionic liquid concentration on the electromechanical response of ionic electroactive polymer actuators. Actuators were fabricated from ionomeric membrane and doped with different concentrations of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ionic liquid. Samples were investigated for their electromechanical and electrochemical characteristics; and it was observed that the maximum electromechanical strain of approximately 1.4% is achieved at 22 wt% ionic liquid content. Increasing ionic liquid concentration results in saturation of the electrode-ionomer interface and formation of ionic double/multi layers, which in turn result in an inward accumulation of ions; hence, generate strain in an undesired direction that deteriorates the electromechanical response of the actuator.

With the growing number of commercial cloud-computing services, there is a corresponding need to verify that such computations were performed correctly. In other words, after a weak client outsources computations to an untrusted cloud, it must be able to ensure the correctness of the results with less work than re-performing the computations. This is referred to as verifiable computation. In this paper we present a new probabilistic verifiable computation method based on a novel Reversible Physically Unclonable Function (PUF) and a binomial Bayesian Inference model. Our scheme links the outsourced software with the cloud-node hardware to provide a proof of the computational integrity and the resultant correctness of the results with high probability. The proposed Reversible SW-PUF is a two-way function capable of computing partial inputs given its outputs. Given the random output signature of a specific instruction in a specific basic block of the program, only the computing platform that originally computed the instruction can accurately regenerate the inputs of the instruction correct within a certain number of bits. To explore the feasibility of the proposed design, the Reversible SW-PUF was implemented in HSPICE using 45 nm technology. The probabilistic verifiable computation scheme was implemented in C++, and the Bayesian Inference model was utilized to estimate the probability of correctness of the results returned from the cloud service. Our proof-of-concept implementation of Reversible SW-PUF exhibits good uniqueness compared to other types of PUFs and exhibits perfect reliability and acceptable randomness. Finally, we demonstrate our verifiable computation approach on a matrix computation. We show that it enables faster verification than existing verification techniques.