Rheological properties
The rheological behavior of the swelled hydrogel was evaluated in triplicate, using a Physica MCR 301 rheometer (Anton Paar GmbH, Austria) equipped with a Rheoplus 32 data analyzer, and fitted with a Peltier temperature control. A 50 mm rough surface coneplate measuring geometry was used to prevent sample slip- page. The temperature of all measurements was kept constant at 298 K. The gap and stain were set at 1.0 mm and 1.0%. Oscillatory shear responses (G′ or storage modulus, and G′′ or loss modulus) were determined at 0.1 Pa over the frequency range of steady shear tests over a share rate range of 0.063–63 rad s−1 . The test conditions were inside the linearity range of the viscoelastic properties.