Improved pressure response with embedded solid microbeads in microfluidic soft sensors

Soft sensors with embedded microchannels filled with liquid conductors have recently been proposed for detecting various types of mechanical stimuli, such as contact pressures, shear forces, strains, and curvatures. Their sensing behaviors are mainly determined by geometrical changes of the embedded microchannels, which is caused by mechanical deformation of the soft structures. In order to control the cross-sectional changes of the microchannels for desired sensor responses, we propose to add solid non-conductive microbeads in the microchannels. Using finite element analysis, we evaluated the influence of the embedded microbeads on the pressure response of soft sensors. We also experimentally compared the pressure responses of soft sensors with rectangular microchannels by changing the number of the beads. Our preliminary results from simulation and experiments showed that the embedded microbeads improved the pressure response of the soft sensors in terms of their linearity, sensitivity, and dynamic range.