Superglue made out of water

Hydrogel superglue was produced for the marine environment and inspired by organisms that fix themselves to underwater surfaces, like mussels.
Interesting Engineering

Scientists turning to nature to find innovative ways to solve a challenging problem is not new. Taking cues from the phenomenon of mussels and barnacles firmly sticking to cliff faces, ship hulls, and even the skin of whales, scientists analyzed the potential of Hydrogel witnessed in such cases. 

To begin with, what is Hydrogel? It is a sticky amalgamation of water and gummy material, which results in a tough and durable bond. 

Researchers at MIT have come up with a way to synthesize sticky hydrogel superglue that is made up of 90 percent water. This is a transparent rubber-like material that adheres to surfaces like Aluminium, Silicom, Titanium, glass, and ceramics. The toughness of the bond is comparable to that of a tendon and cartilage on bones. 

Various experiments have proved the strong adhesive nature of the compound, with objects sustaining a 55-pound weight and silicon wafers sticking onto the gel even after getting shattered. 

Such properties make the material perfect for a protective coating for boats and submarines, and its bio-compatibility could result in its application as a biomedical coating for items like catheters and sensors that are implanted in the human body. 

Xuanhe Zhao, Associate Professor at MIT, explains how the adhesive properties of the Hydrogel are based on its chemical anchorage and bulk dissipation principles. In layman's terms, a Hydrogel can expand significantly without retaining the energy used to stretch it. The chemical properties in the gel enable it to covalently bond its polymer network to the surface of the material. The same principle is harnessed by our human body in the case of tendons and cartilage. 

Zhao also projects the potential of this soft and sticky material with a wide range of possible uses in the future. 

Scientists have ascertained, through adhesive tests of Hydrogel, with different materials like Aluminum, ceramic, glass, and Titanium, that it required an average of 1,000 joules per square meter to peel off the Hydrogel from these materials. This is similar to the energy required to separate tendons and cartilage. 

Efforts by researchers to draw comparisons between the new Hydrogel with elastomers, nanoparticle adhesives, and existing hydrogels proved that the former had higher water concentration and superior bonding ability. 

A possible application of Hydrogel in robotic joints was also tested, with small portions of the matter being used to connect short pipes, which is meant to simulate the limbs of a robot.