Viscoelastic and poroelastic mechanical characterization of hydrated gels

Matteo Galli, Kerstyn S.C. Comley, Tamaryn A.V. Shean, Michelle L. Oyen
2009 Journal of Materials Research  
Measurement of the mechanical behavior of hydrated gels is challenging due to a relatively small elastic modulus and dominant time-dependence compared with traditional engineering materials. Here polyacrylamide gel materials are examined using different techniques (indentation, unconfined compression, dynamic mechanical analysis) at different length-scales and considering both viscoelastic and poroelastic mechanical frameworks. Elastic modulus values were similar for nanoindentation and
more » ... ntation and microindentation, but both indentation techniques overestimated elastic modulus values compared with homogeneous loading techniques. Hydraulic and intrinsic permeability values from microindentation tests, deconvoluted using a poroelastic finite element model, were consistent with literature values for gels of the same composition. Although elastic modulus values were comparable for viscoelastic and poroelastic analyses, timedependent behavior was length-scale dependent, supporting the use of a poroelastic, instead of a viscoelastic, framework for future studies of gel mechanical behavior under indentation.
doi:10.1557/jmr.2009.0129 fatcat:mscguj2eyfbp5cvnsfofdusvum