Catégories
Additive manufacturing

Highly Elastic, Transparent, and Conductive 3D-Printed Ionic Composite Hydrogel

Highly Elastic, Transparent, and Conductive 3D-Printed Ionic Composite Hydrogel

Jérémy Odent, Thomas J. Wallin, Wenyang Pan, Kevin Kruemplestaedter, Robert F. Shepherd, and Emmanuel P. Giannelis

Abstract :  Despite extensive progress to engineer hydrogels for a broad range of technologies, practical applications have remained elusive due to their (until recently) poor mechanical properties and lack of fabrication approaches, which constrain active structures to simple geometries. This study demonstrates a family of ionic composite hydrogels with excellent mechanical properties that can be rapidly 3D-printed at high resolution using commercial stereolithography technology. The new material design leverages the dynamic and reversible nature of ionic interactions present in the system with the reinforcement ability of nanoparticles. The composite hydrogels combine within a single platform tunable stiffness, toughness, extensibility, and resiliency behavior not reported previously in other engineered hydrogels. In addition to their excellent mechanical performance, the ionic composites exhibit fast gelling under near-UV exposure, remarkable conductivity, and fast osmotically driven actuation. The design of such ionic composites, which combine a range of tunable properties and can be readily 3D-printed into complex architectures, provides opportunities for a variety of practical applications such as artificial tissue, soft actuators, compliant conductors, and sensors for soft robotics.

Catégories
Additive manufacturing

Hierarchical chemomechanical encoding of multiresponsive hydrogel actuators via 3D printing

Hierarchical chemomechanical encoding of multiresponsive hydrogel actuators via 3D printing

Jérémy Odent, Sophie Vanderstappen, Antoniya Toncheva, Enzo Pichon, Thomas J. Wallin, Kaiyang Wang, Robert F. Shepherd, Philippe Dubois and Jean-Marie Raquez

Abstract :  Inspired by nature, we herein demonstrate a family of multi-responsive hydrogel-based actuators that are encoded with anisotropic swelling behavior to provide rapid and controllable motion. Fabrication of the proposed anisotropy-encoded hydrogel actuators relies on the high resolution stereolithography 3D printing of functionally graded structures made of discrete layers having different volume expansion properties. Three separate synthetic strategies based on (i) asymmetrical distribution of a layer’s surface area to volume ratio via mechanical design, (ii) crosslinking density via UV photo-exposure, or (iii) chemical composition via resin vat exchange have been accordingly demonstrated for developing very smooth gradients within the printed hydrogel-based actuator. Our chemomechanical programming enables fast, reversible, repeatable and multimodal bending actuation in response to any immediate environmental change (i.e. based on osmotic pressure, temperature and pH) from a single printed structure.

Catégories
Additive manufacturing

Tough and Three-Dimensional-Printable Poly(2-methoxyethylacrylate)-Silica COmposite Elastomer with Antiplatelet Adhesion Property

Tough and Three-Dimensional-Printable Poly(2-methoxyethylacrylate)-Silica COmposite Elastomer with Antiplatelet Adhesion Property

Fumio Asai, Takahiro Seki, Ayae Sugawara-Narutaki, Kazuhide Sato, Jérémy Odent, Olivier Coulembier, Jean-Marie Raquez, and Yukikazu Takeoka

Abstract :  Poly(2-methoxyethyl acrylate) (PMEA) has attracted attention as a biocompatible polymer that is used as an antithrombotic coating agent for medical devices, such as during artificial heart and lung fabrication. However, PMEA is a viscous liquid polymer with low Tg, and its physical strength is poor even if a cross-linker is used, so it is difficult to make tough and freestanding objects from it. Here, we design and fabricate a biocompatible elastomer made of tough, self-supporting PMEA−silica composites. The toughness of the composite elastomer increases as a function of silica particle filling, and its stress at break is improved from 0.3 to 6.7 MPa. The fracture energy of the composite elastomer with 39.5 vol % silica particles is up to 15 times higher than that of the cross-linked PMEA with no silica particles and the material demonstrates stress−strain behavior that is similar to that of biological soft tissue, which exhibits nonlinear elasticity. In addition, the composite elastomer shows the potential to be an antithrombotic property, while the results of the platelet adhesion test of the composite elastomer show that the number of adhered platelets is not significantly affected by the silica addition. As the composite elastomer can be rapidly three-dimensionalprinted into complex geometries with high-resolution features, it is expected to contribute to the development of medical devices from readily available materials.