Researchers at IIT Guwahati have developed a water-repellent, conductive textile that converts electricity and sunlight into heat. This innovation aims to protect against the health risks of prolonged exposure to cold, such as blood clotting, breathing difficulties, and weakened immunity.
Published in Nano-Micro-Small, the research was led by Prof Uttam Manna and his team, including Prof Roy P Paily. Extreme cold can be fatal, and traditional solutions like bulky clothing or heaters have limitations. Conductive textiles offer a lightweight alternative, but existing versions often lack durability and water resistance.
The IIT Guwahati team sprayed ultra-thin silver nanowires onto cotton fabric, making it conductive. These nanowires, thinner than a human hair, allow electricity to flow, generating heat while maintaining softness and flexibility. Silver nanowires were chosen for their high conductivity and ability to convert both electricity and sunlight to heat. Their low electrical resistance allows safe electro thermal conversion at low voltage.
To prevent tarnishing, the researchers applied a water-repellent coating inspired by lotus leaves. This coating's microscopic texture causes water to roll off, keeping the textile dry and ensuring long-lasting conductivity, even in damp conditions. The coating also protects against sweat, rain, and spills.
The textile can be powered by a small rechargeable battery or solar energy, maintaining a temperature between 40°C and 60°C for over 10 hours. Tested in wearable knee and elbow bands, it shows promise for providing sustained warmth to those working in cold environments or arthritis patients needing localized heat therapy. Other applications include on-demand water heating and accelerating chemical reactions.
The textile is self-cleanable, breathable, flexible, and scalable, with potential for various controlled heating applications, states Prof. Uttam Manna. The team has filed an Indian patent and is working to integrate the material with miniaturized electronics for product development. They are also seeking industry collaborations for dry thermos-therapy applications, he adds.
