Abstract
Hydrogel actuators in microfluidic devices must endure the forces of aqueous flow, the constraint of device walls, and the restoring force of elastic membranes. In order to assess the capabilities of hydrogels, three experimental techniques for determining the uniaxial tensile properties and functional swelling properties of microscale hydrogel structures have been developed. Tensile tests were conducted to determine Young's modulus and Poisson's ratio at varying degrees of swelling equilibrium. Force response tests were performed to determine the force exerted by cylindrical hydrogel structures on compression platens held at fixed displacement. Particle image velocimetry, a method originally developed to measure velocity fields in fluid flows, was adapted to investigate the deformation rates at various times within hydrogel structures during volumetric swelling. The techniques and sample fabrication methods outlined are applicable to a variety of hydrogel chemistries.
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Johnson, B., Bauer, J.M., Niedermaier, D.J. et al. Experimental techniques for mechanical characterization of hydrogels at the microscale. Experimental Mechanics 44, 21–28 (2004). https://doi.org/10.1007/BF02427971
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DOI: https://doi.org/10.1007/BF02427971