



An extremely reactive artificial skin

Structure and preparation of the hydrogel. Credits: Zhen Jiang et al. 2019

Mechanical properties of the hydrogel: elasticity, strength, hardness. Credits: Zhen Jiang et al. 2019

Towards a more "human" robotics

Bibliography:



Tough, Self‐Healing Hydrogels Capable of Ultrafast Shape Changing



Zhen Jiang Broden Diggle India C. G. Shackleford Luke A. Connal



Volume31, Issue 48



https://doi.org/10.1002/adma.201904956

Research focused on the development of artificial skins could benefit both people with bioprostheses and robotics. In recent years, significant progress has been made in this direction, but none of the prototypes created to date have combined all the properties of human skin. This is today done. Recently, a team of Australian bioengineers has developed a new type of hydrogel that acts as an artificial skin and combines the strength, durability, flexibility and self-regeneration of human skin.This new hydrogel could be used as skin, tendon or muscle. " Thanks to the special chemistry we have incorporated into the hydrogel, it can repair itself after being damaged, as can human skin. Hydrogels are usually fragile, but our material is so strong that it could easily lift heavy objects. It can also change shape as human muscles do, "says chemist Luke Connal of the Australian National University.The creation of a hydrogel that changes shape and has multiple functions has proven to be a permanent challenge for scientists, even with the natural inspiration of jellyfish, sea cucumbers and fly-flyers. While some hydrogels can withstand mechanical stresses, others have self-healing properties, and some have the ability to memorize shapes or change color.As far as UNA researchers know, no one else has been able to incorporate all these functions into one universal gel. By submitting their material to multiple tests, the authors claim to have created the first dynamic hydrogel that is solid, resistant to mechanical stresses, wear-resistant, self-healing and able to change shape and retain memory. The technical details have been published in the journal Advanced Materials.Using this material, the researchers made extremely thin films of "flesh" without any breakage. When these films were heated or cooled, they then changed shape, bending one way or the other before returning to their original state with the right temperature.Unlike many other hydrogels, which can sometimes take 10 minutes or more to change shape, this gel only takes 10 seconds to bend. Here, the key would be the dynamic hydrogen bonds of the gel and the imine (carbon-nitrogen) dynamic bonds, which work together to form "unprecedented properties".Dynamic bonds have a high response to stimuli, making them perfect for environmental adaptation and self-healing, and imine bonds in particular have fast reaction kinetics that can allow rapid self-healing. . In addition, the authors claim that these materials can be easily prepared using simple chemistry, and if other polymers are added to the molecular mixture, perhaps even more functions can be achieved.If the temperature is somehow used as a control, the authors think that this gel could one day be used as an artificial muscle. " In many sci-fi films, we see the most challenging work done by humanoid robots. Our research has taken an important step toward achieving this, "said materials engineer Zhen Jiang. In the meantime, the team hopes to turn their hydrogel into a printable 3D ink.