Wearable hydroxylated MWCNTs/ecoflex composite strain sensor with high comprehensive performance based on electron irradiation

In this work, electron irradiation as a novel and simple method was used to fabricate wearable strain sensors with high comprehensive performance. Hydroxylated multi-walled carbon nanotubes (hydroxylated MWCNTs) were uniformly adsorbed on ecoflex etched by hydrofluoric acid (HF). After electron irradiation, a large number of defects and functional groups were successfully introduced into the hydroxylated MWCNTs/ecoflex, leading to a flexible strain sensor with high comprehensive performance such as ultra-low detection limit, fast response, and wide sensing range. Compared with the unirradiated sensors, the irradiated sensors have an ultra-low detection limit of 0.01% and a wide strain range (the maximum strain of 800%), the maximum gauge factor is increased by 344%, and the response time and recovery time are reduced by 50% and 89.2% respectively. The sensors can be used for monitoring the weak physiological movements and large-scale human movements, which has great potential in health monitoring. The electron irradiation as an activate method can provide a way for mass fabrication of flexible sensors with high comprehensive performance such as ultra-low detection limit and wide sensing range.