A molecular mechanism is proposed for the toughness enhancement observed in double network (DN) hydrogels prepared from poly (2 acrylamido, 2-methyl, 1-propanesulfonicacid) (PAMPS) polyelectrolyte network and polyacrylamide (PAAm) linear polymer. It is an extension of the phenomenological model set forth recently by Gong et al (Macromolecules 2007, 40, 6658-6664). This mechanism rationalizes the changes in molecular structure of the DN-gel constituents observed via in-situ neutron scattering measurements, the composition dependence of the solution viscosity, and the thermodynamic interaction parameters of PAMPS and PAAm molecules obtained previously from neutron scattering studies. More specifically, this proposed mechanism provides an explanation for the observed periodic compositional fluctuations in the micrometer range induced by large strain deformation.
Citation: Journal of Physical Chemistry B
Pub Type: Journals
hydrogels, tough, neutron scattering, stress transfer, molecular model