A breakthrough water-triggered hyperbranched polymer universal adhesive – or HBPA -- utilizing biomimetic technology was recently developed by Tianjin University, according to university officials.

The adhesive was designed by Professor Liu Wenguang from the university’s School of Materials Science and Engineering.

Officials said the innovation faces up to the great challenge to develop underwater adhesives that can be directly applied under water and produce strong adhesion without external stimulation. They added that the development features strong adhesion under water, which breaks the limitation of the need for a hydration layer. It can be applied to the bonding of diverse materials and so can be called the “universal underwater glue”. It has reportedly overcome the problem faced by traditional adhesives, whose adhesion is greatly reduced when blocked by the hydration layer on the surface of the substrate.

A details schematic illustration of the water-triggered strong underwater adhesion

Officiais said the structure of the new adhesive has both a hydrophobic backbone and hydrophilic functional groups, which can be used completely under water – including in sea water or an aqueous medium with a pH of 3-11 -- without any external stimulation. They added that the HBPA exhibits a robust adhesion -- whether for plastics and rubber --for substrates like metals and glass, or for materials with large differences in surface energy.

Images showing how the underwater adhesion works

Meanwhile, compared with the traditional solid adhesives, this kind of adhesive is injectable as a liquid, in which the ester bonds can be hydrolyzed. Therefore it is also suitable for rapidly stopping bleeding and the adhesion of ruptured tissue in the human body. Officials said that in addition, after curing when contacting water, the HBPA shows strong adhesive properties to wood.

Also, compared with conventional products, the new liquid adhesive does not have the problem of evaporating vapor from toxic organic solvents, making it an environmentally benign adhesive. The work was published in a prestigious journal in the materials field, Advanced Materials, with the first author Cui Chunyan, a doctoral candidate at Tianjin University.