Piezoelectric polymers source of innovation for the structural health monitoring of hydrogen tanks

Arkema is a global specialty chemicals company and France’s leading chemical producer. Since 2010 and the acquisition of Piezotech, the Arkema group has been devoting a continuous effort to the development of electroactive fluoropolymers (Piezotech®) for organic, flexible and printed electronics. Piezotech® products have commercial applications in sensors (smartphones, acoustics, smart buildings), actuators (haptic devices) or dielectrics for transistors. In recent years, Arkema has conducted R&D programs to develop new technologies for thermoplastic composites, particularly for the hydrogen market. Hydrogen tanks are necessary for new vehicles to move towards cleaner mobility. Type IV tanks (polymer liner entirely wrapped in a fiber-resin composite) are perfectly adapted to this challenge because they offer an unmatched strength-to-weight ratio.

However, in order to be qualified and to ensure the total confidence and safety of the driver, the tanks must be able to be controlled at any time because many defects or events can occur during their life (cracks, fiber breaks, delamination, impacts etc.). Piezotech piezoelectric polymers (P(VDF-TrFE)) have remarkable potential for monitoring the structural health of hydrogen tanks: high sensitivity to acoustic waves, deformatiod and temperature. They are used in acoustic detection to identify cracks, impacts or in ultrasonic sensors to generate waves and then detect the differences in propagation, thus allowing a fine analysis of the structure.

Compared to standard piezoelectric ceramics, P(VDF-TrFE) sensors can be mounted on curved surfaces because they are flexible. Also, due to their polymeric nature, they can be integrated into the core of composite tanks and can be printed on large surfaces. The absence of toxic and non-recyclable heavy metals, their light weight and low energy consumption make them the materials of choice for the intelligent tanks of tomorrow.

The presentation will focus on the properties of piezoelectric polymeric materials, their characteristics and examples of concrete implementation in the continuous monitoring of hydrogen tanks.