Fish-Like Dual-Bubbling Nanostructured Membranes-Based Actuation System for Enhanced Underwater Sensing

Abstract

Underwater sensing is crucial for sea exploration and guiding underwater vehicles. Artificial flexible or soft sensors with high sensitivity and environmental adaptability can be one promising alternative. However, the current sensors may experience sharp decline of the sensory performance attributed to the heavy water pressure. Here, inspired by the structure of swimming bladder, a fish-like dual-bubbling sensory membrane is developed with undiminished sensitivity by designing integrated actuation system for underwater mechanical sensing. The integrated system includes a morphing layer of soft elastomer for 3D adaptability and a sensing layer of harder elastomer embedded with carbon nanotubes (CNTs), capable of detecting fluctuations as small as 5 Pa at 8 kPa pressure and maintaining stable sensitivity up to 18 kPa. The rational design of modular-actuation sensory system (MASS) allows the adjustment of sensing capability to handle with the higher applied water pressure. Furthermore, the designed sensor is integrated into underwater vehicle to sensitively detect the navigation behaviors and further to monitor external environmental mechanical stimuli even under 1.6 m condition. The proposed design principle is expected to provide guidance for biomimetic underwater sensory or actuating systems.