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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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Smart systems adapt to the surrounding environments in a number of ways. They are capable to scavenge energy from available sources, sense and elaborate external stimuli and adequately react. Electro Active Polymers are playing a main role in the realization of smart systems for applications if fields such as bio inspired and autonomous robotics, medicine, and aerospace. This paper focus on the possibility to use Ionic Polymer Metal Composites as a class of materials relevant to the realization of post silicon smart systems. The three main aspects of this new technology, i.e., fabrication methods, modeling, and applications are described with emphasis to most recent results. Attention is given to main challenges and shortcomings to be solved for technology, modelling, and control of IPMC based devices that need to be solved before this new technology can be fully exploited in real world applications.

Samples of poly(ethylene-iso/terephthalate)-perfluoro polyether multiblock copolymers with perfluoropolyether (PFPE) segments of different lengths have been characterized for surface composition by XPS and angular dependent XPS in order to determine the influence of the length of the PFPE blocks on the surface segregation of fluorine moieties. The results indicated that there was a high surface excess of PFPE when the PFPE blocks had molecular weight (MW) of 2200; for a bulk content of PFPE of about 8%, the amount of PFPE at the surface was 94 wt %. When the MW of PFPE blocks was 3400 or 1200, for the same bulk content of PFPE of about 8%, the surface showed a more limited excess of PFPE (about 46 and 30 wt % for MW 3400 and 1200 respectively). The segregation capability of PFPE blocks was also influenced by the length of polyester segments to which the PFPE blocks are bonded. So, when the fraction of PFPE bonded to very short segments of polyesters was extracted, the surface enrichment was reduced, and for a bulk composition of PFPE of about 6%, the surface amount of PFPE was of 15, 45, and 29% for PFPE with MW of 1200, 2200, and 3400, respectively. These data suggest that surface segregation depends on the MW of the initial PFPE and of the polyester segments bonded to PFPE after polymerization and that there is an optimum MW for PFPE surface segregation; the most favorable conditions are met for PFPE with MW 2200.

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Ionic polymer metal composites (IPMCs) belong to electroactive polymers (EAPs) and have been suggested for various applications due to their light weight and to the fact that they react mechanically when stimulated by an electrical signal and vice versa. Thick IPMCs (3D-IPMCs) have been fabricated by hot pressing several Nafion ® 117 films. Additional post-processes (more cycles of Pt electroless plating and dispersing agents) have been applied to improve the 3D-IPMC performance. The electromechanical response of 3D-IPMCs has been examined by applying electrical signals and measuring the displacement and blocking force produced.