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Abstract The spatial and temporal control of material properties at a distance has yielded many unique innovations including photo-patterning, 3D-printing, and architected material design. To date, most of these innovations have relied on light, heat, sound, or electric current as stimuli for controlling the material properties. Here, we demonstrate that an electric field can induce chemical reactions and subsequent polymerization in composites via piezoelectrically-mediated transduction. The response to an electric field rather than through direct contact with an electrode is mediated by a nanoparticle transducer, i.e., piezoelectric ZnO, which mediates reactions between thiol and alkene monomers, resulting in tunable moduli as a function of voltage, time, and the frequency of the applied AC power. The reactivity of the mixture and the modulus of a naïve material containing these elements can be programmed based on the distribution of the electric field strength. This programmability results in multi-stiffness gels. Additionally, the system can be adjusted for the formation of an electro-adhesive. This simple and generalizable design opens avenues for facile application in adaptive damping and variable-rigidity materials, adhesive, soft robotics, and potentially tissue engineering. 

We computationally investigate a method for spatiotemporally modulating a material's elastic properties, leveraging thermal dependence of elastic moduli, with the goal of inducing nonreciprocal propagation of acoustic waves. Acoustic wave propagation in an aluminum thin film subjected to spatiotemporal boundary heating from one side and constant cooling from the other side was simulated via the finite element method. Material property modulation patterns induced by the asymmetric boundary heating are found to be non-homogenous with depth. Despite these inhomogeneities, it will be shown that such thermoelasticity can still be used to achieve nonreciprocal acoustic wave propagation. 

Abstract In this work, a portable venturi tube capable of measuring bidirectional respiratory flow is developed and correlated the measurements to pulmonary function. Pressure signals are transduced using flexible and compressible capacitive foam sensors embedded into the wall of the device. In this configuration, the sensors are able to provide differential pressure readings, from which the airflow rate passing through the tube could be extrapolated. Utilizing the venturi effect, the geometry of the spirometer tube is designed through finite element analysis to measure respiratory airflow during inhalation and exhalation. The device tube is 3D‐printed and used to measure tidal breathing and deep breathing, along with peak expiratory flow rates, on a healthy individual. This spirometer design allows for easy‐to‐use point‐of‐care diagnoses and has the potential to improve the care of respiratory illnesses.