Hyderabad varsity researchers develop flexible smart material for future wearable sensors

Sleek and see-through wearable sensors with different applications in devices such aselectric switches, computer keyboards, smartphones, healthcare products and touch sensors with a ‘Made in India’ stamp could soon be round the corner.

A new, composite material that can be bent, twisted and stretched with very low optical transparency, developed by researchers of the University of Hyderabad (UoH) promises to make this a reality.

Optically transparent, flexible materials possessing high dielectric constant have applications in a wide range of products such as flexible electronic devices, micro-electromechanical systems(MEMS), wearable sensors and biomedical devices.

The UoH team led by Raj Kishore Dash, an assistant professor at the Advanced Materials and NEMS Lab, School of Engineering Sciences and Technology, has fabricated and developed an optically transparent flexible composite material with almost 88 per cent optical transparency and high dielectric constant.

“We are very excited about this development. The very low optical transparent material can be used for the development of future transparent wearable sensors and biomedical devices” says the team led by Dash and his PhD student Gunda Rajitha.

A crucial issue in the fabrication of the flexible composite material is the uniform dispersion of the filler material in the polymer matrix.

As a consequence of the poor distribution, defects and cracks are induced in the composite which in turn degrades the flexibility of the material.

Since most of the MEMS and sensors generally require higher repeatability and reversible electromechanical response for higher performance and efficiency, a highly flexible material is required. This is where the UoH material scores.

The UoH team developed the material by embedding Graphene, which is a hair-thin layer of carbon inside silicon-based organic polymer called Polydimethylsiloxane (PDMS). The polymer finds wide applications due to its useful properties like biocompatibility, optical transparency, flexibility but no electrical properties. On the other hand, graphene has sound electrical traits.

The research findings have been published online in the journal Sensors and Actuators.