Pressure-insensitive deep-sea flexible temperature sensor for abyssal ocean environment monitoring

Accurate deep-sea temperature observations are essential for understanding global climate change, sea-level rise, and marine ecosystem dynamics, yet conventional sensors rely on rigid titanium housings that prevent conformal integration on curved or moving surfaces. Herein, a miniaturized, ultrathin, and pressure-insensitive flexible temperature sensor is presented for deep ocean exploration. A composite system architecture incorporating a flexible printed circuit, stretchable interconnects, and pressure-robust soft encapsulation, combined with a ratiometric readout strategy, enables high accuracy temperature measurement of ≤±0.04°C across 0–35°C under abyssal ocean environments. A distributed-island layout is proposed to reduce the interfacial shear stress by 16.9% under hydrostatic pressure of 45 MPa. In parallel, a covalent bonding strategy and SiO 2 –fluorosilane composite surface coating improve the interfacial adhesion strength between the sensor and encapsulation by 36.8% and increase the surface water contact angle to 133°, enhancing corrosion resistance and long-term reliability. Field trials to a depth of 4300 m in the western Pacific using the submersible Shenhai Yongshi , together with a 4 × 4 conformal array demonstration, validate the scalability of this flexible-circuit design for distributed deep-sea temperature sensing.