Physicochemical and rheo-mechanical properties of titanium dioxide reinforced sage seed gum nanohybrid hydrogel

Abstract

Sage seed gum (SSG) is a promising biopolymer candidate for utilization and substitution prevalent galactomannan gels of interest in soft biomaterial applications. Herein, physicochemical and rheo-mechanical properties of SSG matrix reinforced by various titanium dioxide (TiO2) nanoparticles loading (0–25wt%) were monitored. Particle size and density of the nanocomposite increased with raising TiO2 content, due to the creation of more compact agglomerated and aggregated microstructure. Increasing the particle size resulted in lower electrophoretic mobility of SSG-TiO2 systems upon nanoparticles addition, confirmed the adsorption of TiO2 on the SSG macromolecule. Mechanical spectra of the SSG-based nanocomposites demonstrated a more solid-like behavior by lower frequency-dependent viscoelastic moduli, suggested a structural decoration of the nanohybrid gels discussed in terms of polymer bridging effect and formation of percolated matrix-particle superstructure. Crucial textural parameters improved with increasing TiO2 until a critical level (15 wt%), after which further increments in filler resulted in a reduction of hardness, adhesiveness and apparent modulus of elasticity. Deformation of rod-like junction zones acting as physical crosslinks in the system and fracture theory were used to explain the strain-stiffening and adhesive behavior of SSG-based gels, respectively. The nanocomposite gels with tunable functional properties might be ideal candidates for biomaterial industry.