A 3D printable and highly stretchable tough hydrogel is developed by combining poly(ethylene glycol) and sodium alginate, which synergize to. Hydrogels are used as scaffolds for tissue engineering, vehicles for drug delivery, actuators for optics and fluidics, and model extracellular matrices for biological. In this investigation, we successfully prepared extremely stretchable, transparent and tough DN hydrogels by using neutral synthetic polymer–poly(vinyl alcohol).

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A similar trend was observed for samples with notches Fig.

The diversity of weak and strong molecular integrations makes hybrid gels of hydrkgels kinds a fertile area of research. A model of fracture of double network gels. Recoverable energy dissipation can also be effected by hydrophobic associations [ 1718 ].

Haraguchi K, Takehisa T. After the first loading the gel does not recover from the damage; on subsequent loadings the fracture energy is much reduced [ ans ]. In both loading and unloading, the rate of stretch was kept constant at 2 per minute.

As the stretch increases, the alginate network unzips progressively [ 23 ], while the polyacrylamide network remains intact, so that the hybrid gel exhibits pronounced hysteresis and little permanent deformation.

The densities of ionic and covalent crosslinks also strongly affect the mechanical behavior of the hybrid gels Supplementary Figs.

High-water-content mouldable hydrogels by mixing clay and a dendritic molecular binder. After the first loading and unloading, the hybrid gel was much weaker if the second loading was applied immediately, and recovered somewhat if the second loading was applied 1 day later Fig. The ionic crosslinker, CaSO4, was fixed at 0. Supplelementary Data Click here to view.

Supplementary Information is linked to the online version of the paper at www.

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The gel was then left in a humid box for 1 day to stabilize the reactions. The alginate gel exhibited pronounced hysteresis and retained significant permanent deformation after unloading. Ionically cross-linked triblock copolymer hydrogels with high strength.

Highly stretchable and tough hydrogels – Semantic Scholar

Hydrogels Search for additional papers on this topic. In many applications, the use of hydrogels is often severely limited by their mechanical properties. Thus, in the hybrid gel the alginate and the polyacrylamide chains both bear loads. Footnotes Supplementary Information is linked to the online version of the paper at www.

New Process for 3D Printing of Highly Stretchable and Tough Hydrogels

In contrast, the polyacrylamide gel showed negligible hysteresis, and the sample fully recovered its original length after unloading. The sample was taken out of the storage and its stress-stretch curve was measured otugh at room temperature.

Microcapsules and microcarriers for in situ cell delivery. By contrast, in a polyacrylamide hydrogel, the polyacrylamide chains form a network by covalent crosslinks.

Hydrogels for soft machines. Lab tests have already shown that the material is even tougher than natural cartilage.

New Process for 3D Printing of Highly Stretchable and Tough Hydrogels

The ionic crosslinks reform during a period of time after the first loading [ 22 ]. J Mater Sci Mater Med. The nominal stress s is defined by the force applied on the deformed gel divided by the cross-sectional area of the undeformed gel. The existing works, however, have demonstrated fracture energy comparable to, or lower than, that of the double-network gels.

When a gel made with hydrophobic bilayers in a hydrophilic polymer network is stretched, the bilayers dissociate and dissipate energy; upon unloading, the bilayers re-assemble, leading to recovery [ 17 ]. Reprints and permissions information is available at www. On the basis of our experimental findings, we discuss mechanisms of deformation and energy dissipation.


The area between the loading and unloading curves of a gel gave the energy dissipated per unit volume Fig. The extremely stretchable hybrid gels are even more remarkable when compared with their parents: After curing, the gel was taken out of the humid box, and water on the surfaces of the gel was removed with N 2 gas for 1 minute. Pioletti Journal of the mechanical behavior of biomedical…. The new method uses a commercially available 3D-printing mechanism, Zhao explains.

Open in a separate window. Once a chain breaks, the energy stored in the entire chain is dissipated. High-water-content mouldable hydrogels by mixing clay and a dendritic molecular binder Qigang WangJustin L.

Here we report hydrogels made of polymers forming networks via ionic and covalent crosslinks. The publisher’s final edited version of this article is available at Nature. Proc R Soc Lond A. Because of the large magnitude of the fracture energy and the pronounced blunting of the notches, we ran a large number of experiments to determine the fracture energy, using three types of specimens, as well as changing the size of the specimens Supplementary Figs.

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When the proportion of acrylamide was increased, the elastic modulus of the hybrid gel was reduced Fig. Correspondence and requests for materials should be addressed to Z. Baumberger T, Ronsin O.

Environment-sensitive hydrogels for drug delivery. Further development is needed to relate macroscopically observed mechanical behavior to microscopic parameters. For example, an alginate hydrogel ruptures when stretched to about 1.

The toughness is attributed to the synergy of two mechanisms: