Look close enough and it becomes apparent that adhesives have been used since long before mankind took to epoxy or cyanoacrylate. Artefacts such as axes fixed with adhesives have been discovered dating back 200,000 years. Prehistoric glues included birch-bark tar, pine pitch and animal-based hide glue. It is clear early humans looked to the forests, grasslands and oceans around them for suitable means to fix materials together. In a world in dire need of more bio-renewable resources it’s important for the development chemists of today to imitate our ancestors and use nature for ideas.
Humans are by no means the only life to utilise adhesives. A surprising source of powerful adhesives is bacteria. One species in particular, the Caulobacter crescentus, produces a sugary substance that can tolerate forces of up to 5 tonnes per square inch, a great deal higher than commercial adhesives. If this adhesive could be mimicked the impact would surely be momentous.
Another amazing feat of adhesion can be witnessed on coastlines all around the world. Molluscs and other crustaceans manage to cling to rocks indefinitely despite being perpetually battered by the ocean. The secret to the molluscs sticking power are unique proteins. A scientist at Oregon state university used what he had learnt about the adhesion of molluscs and has conducted research into modifying soybeans to produce a renewable bio-based adhesive.
It is unclear where the inspiration for the next generation of adhesives will arise but one thing is certain, mother nature holds solutions and provides countless models just waiting to be mastered.