Perfect for the current cold snap...Development of a 'wearable' next-generation heater [Reading Science]

Stable operation even under extreme temperature and humidity
Domestic research team develops "stretchable transparent dielectric heater"
Ionogel-electrode-based design...80% reduction in operating voltage compared with conventional heaters
Confirmed potential for applications in wearables and vehicles

A stretchable transparent heater technology that operates stably even under extreme temperature and humidity conditions has been developed by a Korean research team. It is being evaluated as having significantly expanded the potential for real-life applications such as wearables and smart environmental control by overcoming the environmental stability limitations of existing hydrogel-electrode-based heaters.

The National Research Foundation of Korea (NRF) announced on the 4th that a research team led by Professor Bae Jinwoo at Korea University of Technology and Education (KOREATECH) has developed a "low-voltage-driven stretchable transparent dielectric heater" that combines non-volatile ionogel electrodes with a high-permittivity dielectric layer.

A highly transparent, highly stretchable heater using non-volatile ionogel electrodes for environmental stability. By applying ionogel electrodes containing ionic liquids, the researchers realized a transparent, stretchable heater. The heater reliably maintains heating performance under mechanical deformations such as stretching, twisting, and bending, and in extreme environments including high-temperature/high-humidity and low-temperature/low-humidity conditions, confirming its potential for wearable device applications. Provided by the research team.

Ionogel surpasses hydrogel limits...Performance maintained in extreme heat and cold

As demand for wearable and smart electronic devices has increased in recent years, heater technologies that offer both stretchability and transparency have become increasingly important. However, conventional water-based hydrogel-electrode dielectric heaters have suffered from a sharp decline in performance due to moisture evaporation and absorption in low-temperature/low-humidity or high-temperature/high-humidity environments.

To address these limitations, the research team designed ionogel electrodes, in which non-volatile ionic liquids are immobilized within a polymer matrix, and a high-permittivity PVC gel dielectric layer using covalent bonding. Through this approach, they successfully achieved stretchability, transparency, and environmental stability at the same time.

The developed heater reached 80°C at a voltage of 200 V, which corresponds to approximately an 80% reduction in operating voltage compared with existing hydrogel-electrode-based heaters. In addition, it reached 40°C, a temperature suitable for thermal therapy, even at a relatively low voltage of 100 V, confirming its potential for realization as a low-voltage wearable heater.

Development of an autonomous thermal regulation system using a high-performance transparent stretchable heater. The developed transparent stretchable heater was applied to an autonomous thermal regulation system that operates automatically according to ambient temperature, proving its practicality for wearable heaters, smart greenhouses, and vehicle glass defogging and anti-frosting technologies. Provided by the research team

Extended to autonomous thermal management systems...Demonstrated in wearables, vehicles, and greenhouses

In particular, the new technology operated stably without performance degradation even under harsh environmental conditions spanning a temperature range of 4-80°C and a relative humidity range of 10-80%. This stands in sharp contrast to existing technologies, whose performance deteriorated rapidly in low-temperature/low-humidity and high-temperature/high-humidity environments.

Based on this heater, the research team also implemented an autonomous thermal management system. In this system, the heater automatically switches on when the ambient temperature falls below a preset target temperature, and it was successfully demonstrated in applications such as wearable thermal heaters, smart greenhouses, and vehicle window defogging and de-icing systems.

Professor Bae Jinwoo said, "This study is significant in that it overcomes the environmental stability limitations of hydrogel electrodes through an ionogel-based design," adding, "It can be applied to various real-life fields, including next-generation healthcare, transparent and stretchable electronic systems, and soft robotics." He continued, "We are currently conducting follow-up research to further lower the operating voltage for wearable applications that involve direct contact with the skin."

This research was supported by the Mid-Career Researcher Program of the Ministry of Science and ICT and the National Research Foundation of Korea, as well as the Phase 4 BK21 program of the Ministry of Education. The research results were published on the 2nd in Small, an international journal in the field of materials.