title: The dynamics of a hydrogel strip.
abstract: A hydrogel strip relaxes when it is stretched. The decay in tensile stress can be ascribed primarily to strain-induced swelling of the polymer network--a result that follows from a continuum model of the gel-solvent system. An equation of motion and a linear constitutive law of the polymer network, Darcy's law, and the conservation of mass of the network and interstitial fluid are solved with boundary and initial conditions appropriate for a stress-relaxation experiment. This model predicts that the time constant of decay depends inversely upon the square of the thickness of the sample. This result is confirmed by experiments. In addition, the network shear modulus, mu, bulk modulus, k, and hydraulic permeability, 1/f, which are estimated by non-linear regression, all agree with measurements obtained using other methods.
authors.affiliation: Centro E. Paggio, University of Pisa, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Chiarelli
authors.forename: P J
authors.initials: PJ
authors.lastname: Basser
authors.forename: D
authors.initials: D
authors.lastname: Derossi
authors.forename: S
authors.initials: S
authors.lastname: Goldstein
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004548:Elasticity; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D008956:Models, Chemical; D011092:Polyethylene Glycols / Q000737:chemistry*; D012212:Rheology; D013223:Statistics as Topic
chemical_list: D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D011092:Polyethylene Glycols