Hyderabad varsity researchers develop optically transparent flexible materials

By Author  |  Published: 3rd Jun 2018  9:58 pm

Hyderabad: A team of researchers from the University of Hyderabad (UoH) claimed to have developed an optically transparent flexible composite material that could be utilised for the development of future transparent wearable sensors and biomedical devices.

Optically transparent flexible materials possessing high dielectric constant have tremendous applications in flexible electronics devices, micro-electromechanical systems (MEMS), wearable sensors and biomedical devices.

A crucial issue in the fabrication of the flexible composite materials is the uniform dispersion of the filler material in the polymer matrix, a press release issued by the university said.

Due to poor distribution of the filler material in the polymer matrix, defects and cracks are induced in the composite which degrades the flexibility of the material. As most MEMS and sensors require higher repeatability and reversible electromechanical response, a highly flexible material is required.

A team of researchers led by Dr Raj Kishora Dash, an assistant professor at the Advanced Materials and NEMS Lab., School of Engineering Sciences and Technology, UoH for the first time fabricated and developed an optically transparent flexible composite material with almost 88 per cent optical transparency and high dielectric constant. The material is very flexible and it could be easily bent, twisted and stretched. Gunda Rajitha, research scholar, who has recently submitted her PhD thesis under Dr Dash supervision is co-contributor for this work, the release said.

The researchers have used a simple and facile approach to fabricate a flexible high dielectric constant composite material by employing a very low vol % chemically treated reduced graphene oxide (RGO) as filler material in the PDMS matrix. This process ensures a uniform distribution of the RGO in the PDMS matrix and demonstrates that this composite could be utilized for the development of capacitive-based transparent flexible sensor.

For most of the flexible composite materials, a very low optical transparency has been reported, says Dr.Dash. “We are excited about this development and our group is actively working in this area to fabricate transparent wearable sensors for different applications like transparent keyboard, switches, transparent touch sensor, bio-medical sensors and more to come”, he adds.

This work has been published online in Sensors and Actuators A: Physical 2018,https://doi.org/10.1016/j.sna.2018.04.040, the release said.