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.

Ionic polymer metal composites (IPMCs) are active materials that exhibit a bi-directional electromechanical coupling: a voltage produces membrane bending, while by bending an IPMC membrane a voltage output is obtained.IPMCs are of increasing interest in a number of application fields. More specifically, IPMCs can work in wet environments, even in water, and this represents a valuable capability in a number of applications fields such as underwater robotics, surveillance, and biomedical applications.In this work a totally new model of an active IPMC beam, solicited by a voltage signal and immersed in water, is introduced. The model estimates the moment produced by the applied voltage. Therefore, the classical Euler-Bernoulli cantilever beam theory and the concept of hydrodynamic function are used to describe the interaction between the beam and the water. Knowledge of this interaction allows estimation of the IPMC active beam motion in water.

Electroactive polymers are materials that change their properties (e.g. size and shape) while stimulated by an electric field/current. Conversely, they produce an electrical signal if bent. As both actuators and sensors, they are considered attractive for various applications, e.g. in biomedicine and robotics. Self-sensing actuators made of these materials are still a topic of great interest among researchers. This paper proposes a new self-sensing ionic polymer-metal composite (IPMC) actuating device. By specially patterning the opposite metal electrodes of an IPMC strip, an actuator and a sensor are formed on a single piece of the material. Self-sensitivity is attained by measuring the changing resistance of the sensor part of the structure. This paper introduces the methods for patterning the surface of an IPMC strip and measuring the resistance change during the actuator work cycle, and gives experimental evidence of the suitability of the proposed method for the realization of a smart motion actuator.

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This paper further discusses a concept of creating a self-sensing ionic polymer-metal composite (IPMC) actuating device with patterned surface electrodes where the actuator and sensor elements are separated by a grounded shielding electrode. Different patterning methods are discussed and compared in detail; the presented experimental data give an understanding of the qualitative properties of the patterns created. Finally, an electromechanical model of the device is proposed and validated.