Hydrogels are soft, bio-friendly materials made primarily of water and polymers, commonly used in medical patches, sprays, and adhesives. Despite their excellent adhesive, stretchy, and protective properties, hydrogels lack breathability, which can lead to skin irritation when worn for extended periods. MIT engineers have now developed a novel hydrogel that is both hydrated and permeable to air. This new material retains its softness, stretchiness, and robustness while incorporating tiny channels that allow air to pass through, significantly reducing sweat buildup and making it suitable for prolonged wear.
In experiments, volunteers wore wireless heart monitors attached to their chests with the new breathable hydrogel. After 10 days of regular exercise, the volunteers showed no signs of skin irritation, and the heart monitors maintained clear readings. These results, published in the journal Nature, may lead to the development of breathable bandages, cosmetic masks, and contact lenses, among other products.
Typically, hydrogels consist of about 90% water, making it inherently difficult for air to permeate effectively. Previous attempts to create air-permeable hydrogels involved puncturing holes or adding certain polymers, which either clogged in liquid or compromised hydration. Professor Zhao’s team successfully employed phase separation technology to create a breathable hydrogel.
In their new design, they mixed a small amount of silica aerogel particles with a conventional hydrogel formula. These particles are stable in water and form interconnected tunnels that allow air to flow. After confirming the formation of this breathable network, the team cross-linked the mixture to lock in the structure.
In multiple tests with volunteers, the breathable hydrogel maintained a strong ECG signal during exercise, in contrast to the significant fluctuations seen with conventional gels. After 10,000 cycles of stretching and compression, the hydrogel retained good breathability, with less than a 5% drop in oxygen permeability.
Professor Zhao notes that this research provides a novel approach for fabricating breathable, multifunctional hydrogels, forming a technology platform with broad potential applications.