Durable ionogel withstands 5,000 times its weight while staying soft on skin

The development of soft materials that can reliably function on the human body is important for the future of bioelectronics and wearable medical devices. These materials need to comfortably conform to the skin while being durable enough for everyday use. However, many existing soft materials are easily damaged, limiting their practical applications.

A research team led by Professor Lizhi Xu from the Department of Mechanical Engineering under the Faculty of Engineering at the University of Hong Kong (HKU) has created a new type of ionogel that overcomes this challenge. The material is soft and flexible, yet strong enough to withstand significant mechanical stress, making it ideal for wearable and biomedical applications.

The research is published in the journal Science Advances, in an article titled "High-strength and fracture-resistant ionogels via solvent-tailored interphase cohesion in nanofibrous composite networks."

The ionogel can support over 5,000 times its own weight and has strength comparable to some plastics, all while remaining in excellent contact with the skin. This impressive performance is achieved through a specialized microstructural engineering process that enhances the interactions between the material's components.

"The key is to strengthen the bonds between different parts within the material," said Professor Xu. "This interfacial engineering significantly enhances the mechanical strength, which is vital for real-world biomedical uses."

Beyond its strength, the material is also well-suited for wearable sensors. The team demonstrated that it can accurately monitor physiological signals such as heart activity (ECG) and muscle activity (EMG), with performance comparable to commercial devices.

"Ionogels are ideal for wearable and medical devices because they can deliver stable performance in everyday conditions," explained Dr. He Zhang, the first author of the research. "They are resistant to drying, breathable, antibacterial, and exhibit ionic conductivity, making them suitable for skin-contact electronics."

In addition, the researchers developed a smart electronic bandage using this material. It can deliver medication, provide electrical stimulation, and prevent bacterial infections. In animal studies, this bandage helped wounds heal faster and reduced inflammation.

Provided by The University of Hong Kong