Can Trash Textiles Replace Toxic Coatings?
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A new technique developed by researchers at Cornell University could enable the creation of waterproof coatings for clothing from discarded textiles — a safer and more sustainable alternative to conventional coatings, which are typically made with harsh chemicals and carcinogens.
The method, developed by a team led by Juan Hinestroza, the Rebecca Q. Morgan ’60 Professor of Fiber Science and Apparel Design in Cornell’s College of Human Ecology, involves a low-temperature synthesis process for creating superhydrophobic (waterproof) coatings. Hinestroza’s team is part of the 2030 Project, a Cornell Climate Initiative.
“If we can save one piece of clothing from going into a landfill, then that will be success,” said Hinestroza, noting that Americans discard between 80 and 100 pounds of clothing per person each year.
The new coating is based on a metal-organic framework (MOF) called UiO-66. MOFs are porous crystalline structures that have been used in numerous applications since being pioneered in the 1990s by chemist Omar Yaghi, with whom Hinestroza previously collaborated on a U.S. Department of Defense grant.
In the lab’s latest work, droplets of various liquids — including soda, water, orange juice, sports drink and milk — were shown to bead on top of fabric treated with the MOF coating, while soaking into untreated fabric. The UiO-66 MOF can be synthesized at room temperature using water and ethanol as solvents, avoiding the need for energy-intensive purification or separation processes that typically accompany textile recycling.
Droplets of (left-to-right) soda, water, orange juice, sports drink and milk are shown on a piece fabric with (top) and without (bottom) a UiO-66 metal-organic framework superhydrophobic coating, developed in the lab of Juan Hinestroza of the College of Human Ecology.
Yelin Ko, a doctoral student in the field of fiber science, is the first author of the study, “UiO-66 Inspired Superhydrophobic Coatings Fabricated from Discarded Polyester/Spandex Textiles,” which was published Sept. 21 in ACS Applied Materials & Interfaces. Hinestroza is the senior author; Tamer Uyar, associate professor of fiber science in Cornell’s Department of Human Centered Design, is the other co-author.
The work builds on a 2023 study that demonstrated the chemical breakdown of old clothing to recover polyester compounds for MOF applications in fire resistance, antibacterial finishes and wrinkle resistance. This latest research takes the concept further by applying it directly to develop waterproof coatings.
In the experiments, discarded polyester/spandex fabrics underwent an alkaline depolymerization process to produce disodium terephthalate — a known linker in the synthesis of UiO-66. When exposed to small amounts of ethanol, the UiO-66 MOF assembled onto the textile substrate and exhibited superhydrophobic properties. The presence of spandex fragments modified the typically hydrophilic MOF structure, enhancing its water-repellent capabilities.
The coated fabrics retained their water resistance even after repeated washing and abrasion, demonstrating durability alongside sustainability.
“We must find alternatives to fluorinated finishes, also known as ‘forever chemicals,’” Uyar said. “This study demonstrates how we can achieve functional finishes, including water-repellent and self-cleaning properties, by upcycling textile waste instead of relying on ‘forever chemicals.’”
Hinestroza emphasized that consumer habits play a key role in the environmental footprint of the textile industry.
“It’s very easy to blame the brands or blame the producers, but in the end, they will not produce if you don’t consume,” he said. “And whatever is not being consumed is thrown away. And we want to believe that the problem ends in our garbage cans, but it doesn’t.”
The research was supported by the Cornell Center for Materials Research Shared Facilities, with funding from the National Science Foundation. Additional support came from the Fulbright U.S. Student Program, sponsored by the U.S. Department of State and the Korean-American Educational Commission.
This article was originally published by the Cornell Chronicle. Read the original version by Tom Fleischman here: https://news.cornell.edu/stories/2024/10/waterproof-coating-made-upcycled-textile-waste
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