Papers by Keyword: Polymer Actuator

Abstract: We report a novel high-performance electroactive polymer actuator based on poly (vinylidene fluoride) (i.e., PVDF) and graphene. The PVDF-graphene composite membranes were fabricated through electrospinning method. The electrospun composite membrane has a three-dimensional network structure, high porosity, and large ionic liquid solution uptake which are a prerequisite for high performance dry-type electroactive soft actuators. The conductive poly (3,4-ethylenedioxythiophene)-poly (styrenesulfonate) (PEDOT:PSS) layers were deposited on the surfaces of the composite membrane through dipping-drying method. The electroactive PVDF-graphene actuators under both harmonic and step electrical inputs show larger bending deformation and faster response time than the pure PVDF actuator. X-ray diffusion (XRD) and ionic conductivity testing results for the PVDF-graphene membrane were compared with those of pristine PVDF. Most important, the PVDF-graphene actuator shows much larger bending deformation under low input voltage, and this could be due to the synergistic effects of the higher ionic conductivity of PVDF-graphene membrane and the electrochemical doping processes of the PEDOT:PSS electrode layers.

Abstract: Technologies for space applications are often considered to be rather conservative, aimed at ensuring reliability and robustness. Nevertheless, novel concepts coming from research activities have been and are always the lymph for the development of successful and competitive new solutions. This paper presents new concepts and ideas inspired by natural systems with distributed actuation embedded in their structure, considered as ideal models for possible uses in space applications. Preliminary concepts for possible technical solutions for long-term future implementations are here proposed and briefly analyzed. Peristaltic-like actuations obtained by the use of dielectric elastomer actuators is proposed as one of the most promising solutions. Experimental performances of a single actuation unit are here presented and directions for future implementations are proposed.

Abstract: This paper describes the early conception and latest developments of electroactive polymer (EAP)- based sensors, actuators and power sources, implemented as wearable devices for smart electronic textiles (e-textiles). Such textiles, functioning as multifunctional wearable human interfaces, are today considered relevant promoters of progress and useful tools in several biomedical field, such as biomonitoring, rehabilitation and telemedicine. This paper presents the more performing EAPbased devices developed by our lab and other research groups for sensing, actuating and energy harvesting, with reference to their already demonstrated or potential applicability to electronic textiles.

Abstract: A new thermal bimorph actuator for large out-of-plane displacement is designed, fabricated and tested. The deflecting beam is composed of polyimide, heater, and polyvinyl difluorides with tetrafluoroethylene (PVDF-TrFE). The large difference of coefficient of thermal expansion (CTE) of two polymer layers (polyimide and PVDF-TrFE) can generate a large deflection with relatively small temperature rising. Compared to the most conventional micro actuators based on MEMS (micro-electro mechanical system) technology, a large displacement, over 1 mm at 20 mW, could be achieved. The proposed actuator can find applications where a large vertical displacement is needed while keeping compact overall device size, such as a micro zooming lens, micro mirror, micro valve and optical application.

Abstract: Many publications have demonstrated advantages of smart polymer actuators over the traditional electromagnetic transducers. One of the most significant contributions of the polymers might be their soft actuation mechanism. Hence unlike the traditional actuators, there is morphological freedom for actuator construction that benefits production of either small scale complex mechanisms or human-like applications. Although many different actuation paradigms of polymer actuators presented in previous publications, no significant contributions are made for the actual industrial applications. A noble idea for acquiring controllable actuation is antagonistic drive mechanism of dielectric elastomer. The mechanism provides fairly accurate controllable motion and relatively large actuation forces. A strong dependency to pre-strain of the polymer is however one of the major constraints of the actuator driving mechanism. A detailed characterization of pre-strain effects should be done for the successful construction of the actuators. Hence an experimental and theoretical consideration about mutual effects of pre-strain and actuator performance is to be presented in the present work.

Abstract: Smart polymer based actuators have demonstrated various benefits over the traditional electromagnetic or piezoelectric-material actuators. One of the most significant contributions of the polymers is its soft actuation mechanisms. Hence morphological freedom for actuator construction benefits production of either small scale complex mechanisms or human-like applications. Although many actuation paradigms of polymer actuators are presented in various publications, no significant contributions are made for investigation of modeling and control methods of the material. In the present work, a smart polymer based actuator is constructed. It is then modeled and analyzed for feasible control scheme selection.