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With the assistance of mechanosensory lateral line system, fish can perceive minute water motions in complex underwater environments. Inspired by the constriction within canal nearby canal neuromast in fish lateral line system, we proposed a novel canal artificial lateral line (CALL) device with constriction in canal nearby the sensing element. The designed CALL device consisted of a poly(vinylidene fluoride-trifluoroethylene)/polyimide cantilever as the sensing element and a polydimethylsiloxane (PDMS) microfluid canal. Two types of CALL devices, i.e., CALL with straight canal (S-CALL) and CALL with constriction canal (C-CALL), were developed and characterized employing a dipole source. Experimental results showed that the proposed C-CALL device achieved a pressure gradient detection limit of 0.64 Pa m −1 , which was much lower than the S-CALL device. It indicates that the constriction in the canal nearby the sensing element could enhance the hydrodynamic pressure sensing performance of the CALL device. In addition, the constriction could modify the frequency response of the CALL device, and the C-CALL device achieved higher voltage output than S-CALL in high-frequency domain.

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Marine hydrological information has a significant impact on human development and the utilization of the oceans, which can be monitored with underwater sensors. In the past, ocean research has relied on the use of bulky underwater recorders and sensory telemetry networks. In this study, an integrated flexible sensor is developed for underwater conductivity, temperature, depth, and strain (CTDS) detection. Platinum resistance sensors were used for temperature and strain measurements, conductivity sensors with interdigitated electrodes were used for salinity measurements, and capacitive pressure sensors for depth measurements. Two kinds of flexible capacitive pressure sensors were fabricated with a carbon nanotube/polydimethylsiloxane (CNT/PDMS) bottom electrode and copper/polyimide (Cu/PI) bottom electrode. The sensor with the CNT/PDMS bottom electrode outperformed the sensor with the Cu/PI bottom electrode over a wide pressure range (< 5 MPa) and showed stable capacitance up to 1000 cycles. COMSOL simulations also support our experimental results with high sensitivity of the sensor with a CNT/PDMS bottom electrode. The integrated flexible sensor is durable and lightweight, making it ideal for use as a stationary monitoring sensor or for attachment to a variety of marine animals.