A Hydrogel Adhesive Marine Sensing System: Design, Mechanism, and Applications

Abstract

Marine animals offer a wealth of knowledge that goes beyond their role as a protein source for humans. Through careful observations, they offer valuable insights into the health of our oceans and provide inspiration for the design and control of unmanned underwater vehicles. Additionally, Research into their migrational patterns and response to external stimuli such as sonar, drilling, and offshore energy production is also important for informing government agencies and engineers of the potential effects of such activities on local fauna.

Traditionally, sensors used to gather data from marine animals have been invasive and cumbersome, involving the use of subcutaneous anchors, bolts, or sutures. Traditional methods limit studies to large, resilient animals such as dolphins and whales, while smaller, more fragile animals are understudied. In this study, a hydrogel adhesive marine tagging system has been developed that offers rapid (less than 20 seconds), robust (interfacial toughness > 160 J m−2 ), conformable, and non-invasive sensor integration on a variety of marine tissues, particularly soft and flexible ones. This system was tested on live marine animals with varying topological features, from soft skins to hard shells, to evaluate its effectiveness against current methods. The system is then used to conduct a kinematic study of skate locomotion, using a sensor network deployed across a skate fin, to showcase how this tool could be used to aid bio-inspired robotic studies. Further, hydrogel mechanics and design strategies are also presented, providing a deeper understanding of the adhesive system and its mechanism. Results from the various experiments show that this system has the potential to revolutionize the field by providing a reliable, quick, and non-invasive method of sensor adhesion.