An ultrasensitive flexible force sensor with nature-inspired minimalistic architecture to achieve a detection resolution and threshold of 1 mN for underwater applications

Highly sensitive flexible force sensors enable precise detection of underwater signals for monitoring biological activity, environmental conditions, and vehicle movement. Multilayer stack assembly and micro/nano structure array are often seen in most force/pressure sensors which are toughly hard to control the interlayer spacing and micro/nano structures alignment precisely, resulting in poor consistency and stability. Herein, we first reported a new force sensor with a nature-inspired minimalistic architecture, addressing such issues in an elegant and surprising approach by using a single-layer arched functional membrane with one microgroove. Inspired by the scorpions' slit sensilla and mantis' campaniform sensilla, a highly sensitive and waterproof flexible force sensor was fabricated. It is demonstrated that the force sensor has a sensitivity of 27.6 N-1, a high force resolution (1 mN), a fast response time of 70 ms, excellent stability over 5000 cycles and linearity (0.996), and a small force detection limit (<= 1 mN), showing great potential in underwater environment sensing and motion monitoring of vehicles. This novel but minimalistic architecture provides a new direction in the development of sensors with advanced performance.