Structure and rheology of nanocomposite hydrogels composed of DNA and clay

[Display omitted] ► The interaction between PO2- and SWN surfaces. ► DNA/SWN hydrogels exhibited viscoelastic solid-like properties. ► The softening of the nanocomposite hydrogels occurred. ► The initial network structure was ruptured accompanied with the lack of the longest relaxation time. The preparation and characterization of the nanocomposite hydrogels based on deoxyribonucleic acid (DNA) and synthetic hectorite (SWN), were reported. Wide-Angle X-ray Diffraction (WAXD) and Fourier Transform Infrared Spectroscopy (FTIR) analyses confirmed that the intercalation of water molecules into the silicate galleries took place and the interaction between PO2- groups of DNA and SWN surfaces. DNA/SWN hydrogels exhibited viscoelastic solid-like properties DNA as revealed by rheological measurements. The stress-relaxation behaviors of DNA/SWN and SWN hydrogels in the linear viscoelastic regime and non-linear viscoelastic regime were examined. The incorporation of DNA macromolecules led to the enhancement of the damping behavior of the dispersed silicate particles as compared with SWN hydrogels without DNA. The softening of the nanocomposite hydrogels was supported by the calculated damping function of the stress-relaxation measurements.