MEchanics GAthering -MEGA- Seminar: Soft conductive fibers for mechanical sensing

The integration of conductive elements in soft material constructs provides attractive opportunities for the realization of diverse electromechanical devices. Flexible mechanical sensors, in particular, offer a wide application range in health monitoring, human-machine interaction, and soft robotics. However, their implementation in functional textiles is limited because existing devices are usually small, 0D elements, and spatially resolved sensing is only achieved through arrays of sensors that are difficult to integrate and include many failure-susceptible connections. In this talk, we will present a class of soft and conductive fibers tailored for the sensing of mechanical stimuli on large, flexible surfaces. The scalable thermal drawing technique is employed to co-process electrical materials, such as polymer composites or liquid metals, within a soft thermoplastic elastomer support into long fibers with customizable architectures. Controlled deformations of the fibers’ microstructure, in the form of compression or elongation, induce detectable, predictable, and reversible changes in electrical characteristics. Experimental and theoretical knowledge about the coupling of the fibers’ mechanical and electrical properties forms the basis for the design of fiber-based sensors that are capable of reliably assessing mechanical stimuli. The potential of the 1D sensors in health care is demonstrated by measuring pressures on a gymnastic mat for the monitoring of body position, posture, and motion.