The latest coatings research has taken a tasty turn toward ingredients that non-chemists can not only pronounce, but actually consume: Wine. Tea. Chocolate.
The new recipe comes from Northwestern University, where scientists have developed multifunctional anti-bacterial coatings based on the sticky polyphenols found in red wine, green tea, dark chocolate and cacao beans, the Evanston, IL-based university said in a press announcement.
The team put the stickiness of plant polyphenols— behind the "astringency" effect some people experience when drinking red wine high in tannins—to work in a new way.
Polyphenols are naturally occurring molecules found in plants whose functions include structural support and defense against bacteria and oxidative damage, the researchers explain.
Tannic acid and pyrogallol—inexpensive compounds resembling the more complex polyphenols found in tea, wine and chocolate—were used in the coating development, according to the scientists.
The team’s research, “Colorless Multifunctional Coatings Inspired by Polyphenols Found in Tea, Chocolate and Wine,” was published Aug. 22 in the journal Angewandte Chemie.
Dissolving polyphenol powder in water with a small amount of salt quickly produces transparent coatings that have antioxidant properties, are non-toxic, and can kill bacteria on contact, the university reported.
The coatings can reportedly stick to virtually any surface, including Teflon, and are about 20 to 100 nanometers thick.
“The stickiness of plant polyphenols is behind the so-called astringency effect that people can experience when drinking red wine high in tannins,” explains Phillip B. Messersmith, professor of Biomedical Engineering at Northwestern’s McCormick School of Engineering and Applied Science. Messersmith led the research.
“The tannins stick to, or bind, saliva proteins, producing the sensation of puckering and dryness.
“We’ve put this stickiness to work in a novel way,” he added.
The potential uses for the coatings are numerous, including consumer, industrial and medical products, the researchers report.
Catheters and orthopedic implants to membranes for water purification and materials used in food processing, packaging and preparation were specifically mentioned. The university did not immediately respond to a request for more information regarding potential architectural uses for the coatings.
Baxter Healthcare and the National Institutes of Health supported the research.