Can Trash Textiles Replace Toxic Coatings?

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.

Yelin Ko/Provided

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.