Balloon‐Embedded Sensors Withstanding Extreme Multiaxial Stretching and Global Bending Mechanical Stress: Towards Environmental and Security Monitoring

Balloon‐embedded stretchable sensors, undergoing a simultaneous equal‐multiaxial stretching along global bending motion, have been characterized and tested towards environmental and security monitoring missions. Stress‐enduring inks are printed on the curvilinear surface of conventional rubber balloons and their resilience to extreme mechanical deformations, associated with repeated inflation and deflation cycles, is investigated. Unlike early studies of mechanical deformed electrochemical devices—performed with linear stretching or bending—the present balloon‐embedded sensors undergo simultaneous multidimensional strains without any alteration of its electrochemical properties. Careful attention is given to the elastomeric, electrical, and electrochemical properties of the new expandable composite inks for addressing the extreme demands of the inflated spherical dynamic balloon substrate. The influence of the balloon inflation and corresponding multiaxial mechanical stress upon the electrochemical behavior is modeled analytically. The electrochemical detection of relevant military and homemade explosives in liquid and vapor phases is used to demonstrate the functionality and potential of the new balloon sensor system to diverse environmental and defense missions. Negligible changes in the response to explosive compounds are observed following multiple repeated inflation and deflation cycles, involving over 400% increase of the balloon area.