Flexible Thin-Film Temperature Sensors on Gelatin-Based Biodegradable Substrates for the Development of Green Electronics

The rapid growth in usage of disposable single-use plastics is posing a problem for the environment and the ecosystems of the planet. Many efforts are being put together to reduce the impact coming from these polymers by developing environmentally-friendly approaches that substitute traditional methods of fabrication and materials for thin-film electronics. Using biodegradable materials for the development of substrates for single-use electronics is a promising approach towards this goal. In this work, two types of gelatin substrates were developed, one being gelatin-glycerol, and the other being gelatin-emulsifier, to tune their degradation properties without compromising their capability for thin-film electronics fabrication, with degradation time of 15 days and 5 days, respectively. As a demonstration, thin-film temperature sensors were fabricated on the substrates and their response was analyzed over a temperature range of 5 °C-60 °C. The temperature coefficient of resistance of the sensors fabricated on the gelatin-glycerol and gelatin-emulsifier was 0.0024 °C
⁻¹
and 0.0046 °C
⁻¹
, respectively. The use of green materials to create substrates for thin-film electronics applications is paving the way for the reduction of plastic usage and the harmful impact that the presence of these polymers have in nature.