NOVEL ELECTROACTIVE SOFT ACTUATORS BASED ON IONIC GEL/GOLD NANOCOMPOSITES PRODUCED BY SUPERSONIC CLUSTER BEAM IMPLANTATION
Tesi di Dottorato
Data di Pubblicazione:
2017
Citazione:
NOVEL ELECTROACTIVE SOFT ACTUATORS BASED ON IONIC GEL/GOLD NANOCOMPOSITES PRODUCED BY SUPERSONIC CLUSTER BEAM IMPLANTATION / Y. Yan ; internal advisor: Alessandro Podestà; external supervisor:Yosi Shacham ; supervisor: Paolo Milani. DIPARTIMENTO DI FISICA, 2017 Mar 02. 28. ciclo, Anno Accademico 2016. [10.13130/yan-yunsong_phd2017-03-02].
Abstract:
Ionic electro-active polymers (IEAPs) constitute a promising solution for developing self-regulating, flexible and adaptive mechanical actuators in the area of soft robotics, micromanipulation and rehabilitation. These smart materials have the ability to undergo large bending deformations as a function of a low applied voltage (1 to 5 V), as a result of the ions migration through their inner structure when the network is liquid filled. Among this broad family of materials, ionic-polymer-metal composites (IPMC) based on DuPont’s Nafion® have attracted an increasing interest for the production of light weight controllable soft machines due to their easiness to be metalized (e.g. by mean of electroless plating), fast response and capability of working exposed to air. However, the high cost of the material, its relatively low working density (i.e. the maximum mechanical work output per unit volume of active material that drives the actuation) and weak force output, as well as the considerable fatigue effects endured by the surface electrodes upon cycling, is limiting the performance of these IPMC actuators and hindering their implementation in traditional mechatronic and robotic systems. On the other hand, ionic hydrogels, such as poly(acrylic acid) (PAA) and poly-styrene sulfonate (PSS) based polymers, exhibit controllable mechanical properties and porosity and have shown to be excellent candidates to be used as electrically triggered artificial muscles and miniaturized robots operating in aqueous environments. Although the relatively low cost of these materials render them appealing for mass production scale up, the applicability of these polymeric actuators is limited to a liquid environment, which is intrinsically facilitating the solvent evaporation when the hydrogels are exposed to air. Furthermore, because of the difficulty encountered in fabricating stable and anchored metal structures on these polymer surfaces, these smart soft systems operate in a non-contact configuration with respect to the pilot electrodes, therefore increasing the actuators response time up to few tenths of seconds. In order to achieve an efficient electromechanical transduction along with a stable and durable performance for electro-active actuators operating in air, two main interplaying characteristics must be tailored when designing the system. On one hand side, the need of electrodes that are physically interpenetrating with the polymeric basis is of absolute priority, since the intercalation of ions into the electrode layers and the resulting material volumetric change are fundamental for strain generation. On the other hand, the formulation and engineering of new low cost materials able to merge highly elastic properties and efficient ionic transport features is of crucial importance.
The present thesis work deals with the formulation, synthesis and manufacturing of a novel ionic gel/metal nanocomposite (IGMN) that was designed and developed to merge the advantageous properties of both IPMCs and ionic hydrogel actuators and to contextually overcome many of the above mentioned drawbacks characteristic of these two families of polymers. These composites were obtained by mean of Supersonic Cluster Beam Implantation (SCBI). This technique, developed in-house, relies on the use of supersonically accelerated gas-phase metal cluster beams directed onto a polymeric substrate in order to generate thin conductive layers (few tenths to few hundreds of nanometers thick) anchored to the polymer. This scalable approach already proved to be suitable for the manufacturing of elastomer/metal functional nanocomposites, and, as described in this work, it enabled the production of cluster-assembled gold electrodes (100 nm thick) interpenetrating with an engine
Tipologia IRIS:
Tesi di dottorato
Keywords:
Ionic polymer metal composites,electro-active polymer, halloysite nanoclays.
Elenco autori:
Y. Yan
Link alla scheda completa:
Link al Full Text: