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Home page > LPCNO > Seminars > 2015 > Hydrogel Actuation by Electric Field Driven Effects

Hydrogel Actuation by Electric Field Driven Effects

Date : 26/11/2015 à 14:00

Titre : Hydrogel Actuation by Electric Field Driven Effects.

Intervenant : Daniel Morales

Provenance : Nanotech Group@LPCNO

Salle : Salle de Séminaire - LPCNO

Résumé: ’Intelligent’ soft matter systems can sense and adjust their shape in response to the external environment and will be used towards the development of new composite systems, metamaterials, and soft robotic components. Stimuli responsive soft materials must combine evermore complex and precise response mechanisms in order to rival the reliability and speed of conventional devices made of hard materials. While pneumatic elastomer systems have shown promise for soft robotics applications, hydrogels provide a true biomimetic material since they resemble organic tissues in terms of mechanical properties and water content. Hydrogels are networks of crosslinked, hydrophilic polymers capable of absorbing and releasing large amounts of water while maintaining their structural integrity. Polyelectrolyte hydrogels are a subset of hydrogels that contain ionizable moieties, which render the network sensitive to pH and ionic strength and provide mobile counterions, which impart conductivity. My work utilizes electric field driven effects to manipulate the interaction of ions within polyelectrolyte hydrogels in order to induce controlled deformation and patterning. In the first part of this talk, I describe the integration of cationic and anionic gel appendages for the first time to develop walking hydrogels which mimic the locomotion of the inchworm. The two separate gel networks were attached by electric field promoted adhesion. The oppositely charged appendages of the resulting device bent in opposite directions in response to an electric field. Thus, switching the direction of the electric field caused the appendages to open and close, allowing the device to ‘walk’. In the second part, I discuss a new technique to incorporate exoskeletal structures into soft, hydrogel networks to pattern and program their shape change in air and in solution. The technique, named ionoprinting, relies on the oxidation and release of transitional metal ions from an anode in contact with an ionic hydrogel. In the third part of this talk, I describe how electric fields can be used to promote the interactions of separate gel networks, as modular multi-responsive components, and particle assemblies within gel networks to develop new types of soft composite systems. Overall, this work illustrates the promise of electric field driven techniques such as ionoprinting and electro-adhesion to rapidly produce complex gel systems using simple benchtop equipment