This paper introduces a comprehensive nonlinear dynamic model of motion actuators based on ionic polymer metal composites (IPMCs) working in air. Significant quantities ruling the acting properties of IPMC-based actuators are taken into account. The model is organized as follows. As a first step, the dependence of the IPMC absorbed current on the voltage applied across its thickness is taken into account; a nonlinear circuit model is proposed to describe this relationship. In a second step the transduction of the absorbed current into the IPMC mechanical reaction is modelled. The model resulting from the cascade of both the electrical and the electromechanical stages represents a novel contribution in the field of IPMCs, capable of describing the electromechanical behaviour of these materials and predicting relevant quantities in a large range of applied signals. The effect of actuator scaling is also investigated, giving interesting support to the activities involved in the design of actuating devices based on these novel materials. Evidence of the excellent agreement between the estimations obtained by using the proposed model and experimental signals is given.

This paper introduces a comprehensive model of sensors based on ionic polymer metal composites (IPMCs) working in air. Significant quantities ruling the sensing properties of IPMC-based sensors are taken into account and the dynamics of the sensors are modelled.A large amount of experimental evidence is given for the excellent agreement between estimations obtained using the proposed model and the observed signals.Furthermore, the effect of sensor scaling is investigated, giving interesting support to the activities involved in the design of sensing devices based on these novel materials.We observed that the need for a wet environment is not a key issue for IPMC-based sensors to work well. This fact allows us to put IPMC-based sensors in a totally different light to the corresponding actuators, showing that sensors do not suffer from the same drawbacks.

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Harvesting systems capable of transforming dusty environmental energy into electrical energy have aroused considerable interest in the last two decades. Several research works have focused on the transformation of mechanical environmental vibrations into electrical energy. Most of the research activity refers to classic piezoelectric ceramic materials, but more recently piezoelectric polymer materials have been considered. In this paper, a novel point of view regarding harvesting systems is proposed: using ionic polymer metal composites (IPMCs) as generating materials.The goal of this paper is the development of a model able to predict the energy harvesting capabilities of an IPMC material working in air. The model is developed by using the vibration transmission theory of an Euler-Bernoulli cantilever IPMC beam. The IPMC is considered to work in its linear elastic region with a viscous damping contribution ranging from 0.1 to 100 Hz. An identification process based on experimental measurements performed on a Nafion ® 117 membrane is used to estimate the material parameters. The model validation shows a good agreement between simulated and experimental results.The model is used to predict the optimal working region and the optimal geometrical parameters for the maximum power generation capacity of a specific membrane. The model takes into account two restrictions. The first is due to the beam theory, which imposes a maximum ratio of 0.5 between the cantilever width and length. The second restriction is to force the cantilever to oscillate with a specific strain; in this paper a 0.3% strain is considered. By considering these two assumptions as constraints on the model, it is seen that IPMC materials could be used as low-power generators in a low-frequency region. The optimal dimensions for the Nafion ® 117 membrane are length = 12 cm and width = 6.2 cm, and the electric power generation is 3 nW at a vibrating frequency of 7.09 rad s −1 . IPMC materials can sustain big yield strains, so by increasing the strain allowed on the material the power will increase dramatically, the expected values being up to a few microwatts.

In this paper, a first prototype of a multifunctional tactile sensor using ionic polymer metal composites (IPMCs) is proposed, designed, and tested. Two IPMC strips are used, one as an actuator and one as a sensor, both positioned in a cantilever configuration; working together they enable the system to detect the presence of a material in contact with it and to measure its stiffness. These sensing capabilities can be exploited in various biomedical applications, such as catheterism, laparoscopy and the surgical resection of tumors. Moreover, the simple structure of the proposed tactile sensor can easily be extended to devices in which a sensing tip for exploration of the surrounding environment is required. Compared with other similar tools, the one proposed works with a very low-power supply (the order of magnitude being a few volts), it needs very simple electronics, it is very lightweight and has a low cost.To the authors' knowledge, the research activity presented here is one of the first IPMC working applications in the biomedical field and represents a valid example of IPMC capabilities.