Carbon black-PDMS composite conformal pressure sensor arrays for near-body flow detection

In nature, fish rely on the lateral line sensory organ for many critical behaviors including obstacle detection, prey tracking, and schooling. Acting in a similar fashion to an array of pressure sensors, the lateral line allows for the detection of near-body flow structures such as vortex shedding and separated flow. Drawing on the lateral line for inspiration, conformal and highly sensitive pressure sensor arrays were investigated using a carbon black and polydimethylsiloxane (CBPDMS) composite as a piezoresistive sensing material. In order to achieve the sensitivity necessary for the detection of hydrodynamic stimulus while maintaining the flexibility and robustness for use in the maritime environment, a porous CBPDMS composite was developed using sugar as a sacrificial scaffold. When the sacrificial scaffold was dissolved, the Young's modulus of the porous composite was reduced nearly two orders of magnitude compared to solid CBPDMS, leading to an order of magnitude increase in array sensitivity. The porous CBPDMS active material was packaged as an underwater sensing array using multiple encapsulation methods, and successfully tested using water wave stimulus in the MIT Towing Tank.