Aaron Mena (left) and Jennifer Garcia Rodriguez, graduate students in Purdue University’s Department of Chemistry, affix corals using adhesive formulations developed from fully sustainable, bio-based components. Credit: Purdue University photo/Gudrun Schmidt
Key points:
- A research group at Purdue University has developed a sustainable, bio-based adhesive formulation that can be used underwater or in wet conditions.
- The adhesive is based on inexpensive, sustainably sourced and plant-based materials, and can be made simply and rapidly anywhere.
- The adhesive has a variety of potential uses, including construction, manufacturing, food, oral, cosmetic applications and coral reef restoration.
A new study, published in ACS Applied Materials & Interfaces, describes the development of a new adhesive formulation from sustainable, bio-based components that can be used underwater or in wet conditions.
The research group at Purdue University developed their patent-pending adhesive formulation from zein, a protein found in corn, and tannic acid. They tested their formulation using different surfaces and different waters including seawater, saline solution, tap water, and deionized water.
“Interestingly, the water type does not influence performance a great deal, but the substrate type does,” said study author Gudrun Schmidt. “An additional unexpected result was bond strengths increasing over time when exposed to water, suggesting that water helps to make the glue stick underwater.”
Protective skin formed on the adhesive surface when it was placed underwater, which prevented water from entering the rest of the material. Additionally, maximum bonding occurred at about 30 degrees Celsius, then another increase at higher temperatures.
The team was able to develop their formulation from inexpensive, sustainably sourced, and plant-based materials, which sets their adhesive apart from other fully synthetic glues. Importantly, the adhesives can be made simply and rapidly both in the lab or even outdoors.
The nontoxic adhesive formulation may be further developed for other applications that require a wet adhesive including use in construction and manufacturing as well as in the biomedical, dental, food, and cosmetic industries.
Another application for the formulation is the restoration of coral reefs, where researchers hope to develop a suitable underwater adhesive to plant young coral reefs on structures that have died. Schmidt and her team have sent multiple formulations to the Coral Restoration Foundation (CRF) to be tested.
“Field preliminary results are very encouraging, and we’ll continue to provide feedback to Purdue researchers to ensure the final product is consistently successful across multiple restoration goals,” said Phanor Montoya-Maya, coral restoration program manager at CRF.