A MULTIFUNCTIONAL AND RECONFIGURABLE MICROVASCULAR COMPOSITE

Fiber-reinforced polymer (FRP) composites, consisting of stiff/strong fibers embedded within a continuous matrix, are a lightweight structural platform supporting an array of modern applications. Bioinspired vascularization of fiber-composites can augment existing performance with dynamic functionalities via liquid infiltration of the internal micro-fluidic network. Some vascular-enabled capabilities include self-healing to repair delamination damage and active-cooling to prevent thermal degradation. While such attributes have been demonstrated in separate platforms, research investigations that combine functionalities within a single composite have been limited. Here we provide a recent study that highlights a promising pathway for achieving both multifunctional, and reconfigurable behavior in microvascular FRP composites. Specifically, we detail the ability to regulate temperature and modulate electromagnetic signature via fluid substitution within the same serpentine vasculature. Varying microchannel density alters both active-cooling efficiency by water circulation and polarized radio-frequency wave reflection by liquid metal infiltration. We control these bulk property pluralities by widespread vascularization, while minimizing impact on structural performance, and decode the effects of micro-vascular topology on macromechanical behavior. Our in-depth experimental and computational investigation provides a new benchmark for future design optimization and real-world translation of multifunctional and adaptive microvascular composites.

DEVELOPMENT OF A RF BIOSENSOR DESIGN TO DETECT CHANGES IN SCATTERING PARAMETERS OF AQUEOUS MATERIALS DURING RADIO FREQUENCY WAVE EXPOSURE

The advancing field of biosensor design continues pushing for smaller, inexpensive, yet accurate sensor designs. A subset of biosensors operating in the radio frequency (RF) range of electromagnetic (EM) waves, called RF biosensors, offer appeal as a non-destructive, non-invasive form of sensing. A novel RF biosensor is proposed which detects changes in scattering parameter measurements of a microliter, aqueous material under test (MUT) held within a well adjacent to a microstrip transmission line. This sensing design measures scattering parameter data and changes in these measurements offer insight into the effects of RF wave exposure on dielectric materials within the well. The following paper describes design considerations and the sensing technique of the proposed RF biosensor. Simulations were run in incremental steps to first, establish the simulation design of a 50-ohm microstrip transmission line using two software packages ADS and Ansys HFSS. Next, experimental measurements were collected by milling the RF biosensor, first using air and then distilled water as the MUT, and finally comparing to simulations to establish validity of the novel sensing device. Next, experimental S-parameter measurements were obtained and compared between the two test cases to determine if a difference could be detected. Both simulated and experimentally obtained measurements suggest the designed RF biosensor can detect changes in the MUT loaded inside its etched well and therefore can be used as a sensing device.