Thermally-triggered free-standing shape-memory actuators
This investigation presents a new approach to obtain free-standing thermally-triggered “two-way” shape-memory actuators by realizing multilayer structures constituted by glassy thermoset (GT) films anchored to a previously programmed liquid-crystalline network (LCN) film. The GT is obtained via dual...
| Autores: | , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2017 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/113530 |
| Acceso en línea: | https://hdl.handle.net/2117/113530 https://dx.doi.org/10.1016/j.eurpolymj.2017.10.006 |
| Access Level: | acceso abierto |
| Palabra clave: | Actuators Crystalline polymers Click chemistry Dual-curing Liquid-crystalline network Shape memory polymers Thermally-triggered actuators Actuadors Polímers cristal·lins Àrees temàtiques de la UPC::Enginyeria dels materials::Materials plàstics i polímers |
| Sumario: | This investigation presents a new approach to obtain free-standing thermally-triggered “two-way” shape-memory actuators by realizing multilayer structures constituted by glassy thermoset (GT) films anchored to a previously programmed liquid-crystalline network (LCN) film. The GT is obtained via dual-curing of off-stoichiometric “thiol-epoxy” mixtures, thus enabling the development of complex actuator configurations thanks to the easy processing in the intermediate stage, and a compact and resistant design due to the strong adhesion between the layers obtained upon the final curing stage of the GT. A model based on the classical multilayered beam theory to predict the maximum deflection of a “beam-like” design is proposed and its reliability is verified by experimental investigation of actuators with different configurations and LCN stretching levels. The results show the capability of these actuators to bend and unbend under various consecutive heating–cooling procedures in a controlled way. The maximum deflection can be modulated through the configuration and the LCN stretching level, showing an excellent fitting with the model predictions. The model is able to predict high actuation levels (angles of curvature ˜ 180°) and the bidirectional shape-memory behavior of the device as a function of the thickness, configuration of the layers, and the LCN stretching level. This approach enables the design of free-standing two-way actuators covering a range of bending actuation from 27 to 98% of the theoretical maximum deflection. |
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