Researchers at IIT Guwahati have developed a new water-repellent material
Researchers at the Indian Institute of Technology (IIT) in Guwahati have developed a new water-repellent material that can be used for real-time monitoring of human movement. The developed material is flexible, non-stretchable and environmentally friendly which can sense low stress with high sensitivity.
Wearable motion sensors are used for physiological monitoring of human movements. These sensors are used for gait analysis, understanding human-machine interactions and monitoring patients during rehabilitation processes. Such motion sensors are generally made of materials that convert the mechanical stress resulting from movement into detectable electrical signals.
The research team has developed such a material which is superior to existing strain sensors in terms of sensitivity and durability.
The research team was led by Dr Uttam Manna, Associate Professor, Department of Chemistry, Center for Nanotechnology and School of Health Sciences and Technology, IIT Guwahati and Professor Roy Paily, Department of Electronics and Electrical Engineering, Nanotechnology Center and School of Health Science and Technology, IIT Guwahati.
The results of their groundbreaking and unprecedented work were recently published in the renowned peer-reviewed journal Materials Horizons. Dr Uttam Manna and Professor Roy Paily co-authored the article with Supriya Das, Rajan Singh, Avijit Das, Sudipta Bag from IIT Guwahati.
Explaining how their product works, Dr Uttam Manna, Associate Professor, Department of Chemistry, Center for Nanotechnology and School of Health Sciences and Technology, IIT Guwahati, said, âStress sensors convert mechanical deformation into electrical signals. The efficiency of converting mechanical strain into an electrical signal depends on the gauge factor of the material – the ratio of the relative change in the electrical resistance of the material to the mechanical stress. Thus, a high gauge factor would mean greater sensitivity of the sensor.
Until now, portable strain sensors have used the material stretch feature to measure strain. These sensors were made of polymers or fabrics in which were embedded nanoparticles of specialized materials. The constant stretching used to detect movement causes fatigue and material failure over time.
The researchers developed a metal-free, chemically reactive and conductive ink, which they coated onto chemically reactive paper in a specific pattern. The patterned interface developed by the IIT Guwahati team has been shown to be abrasion tolerant, highly water repellent and sensitive to low stress levels. It had a high gauge factor of about 18,300 with an applied stress of 0.2% and responded to applied mechanical stress in 8 milliseconds. The material was also stable over time and through many operating cycles.
Explaining how the sensors can be used, Dr Uttam Manna said: âThe ink pattern paper was connected to an electronic component and a Bluetooth module and attached to various parts of the human body for wireless monitoring of different movements. and human expressions. It was attached to the finger to detect flexion movements, to the knee to detect walking and squatting movements, and to different parts of the face to detect facial expressions.
Further, Dr Uttam Manna added: âThe sensor was so sensitive that it could differentiate smile from laughter and could detect swallowing motion. Attaching the model interface to the wrist allowed the wrist pulse to be monitored. The extreme waterproofness of the material also makes it suitable for use underwater.
The current and simple design of the superhydrophobic and conductive pattern interface has immense potential for different and more realistic applications. The unconventional interface developed by the IIT Guwahati team holds promise for the development of devices in various fields, including healthcare, human-machine interactions, and energy harvesting.