Viscoelastic and rheological properties of nanocomposite-forming solutions based on gelatin and montmorillonite

•The montmorillonite changes the sol-gel transitions of gelatin-based solutions.•The nanocomposite-forming solution (in sol domain) presents a non-Newtonian.•The mean diameter and ζ-potential of nanoparticle dispersed in water varies with its concentration.•The behavior of gelatin-based solution can be due to formation of coacervates.

Interested in developing gelatin-based nanocomposites using a spreading technique, this research aimed to study the effect of nanoparticles concentration on the rheological properties of nanocomposite-forming solutions (NFS) based on gelatin and montmorillonite (MMT). The NFS were produced with 5 and 8 g gelatin/100 g NFS; 30 g glycerol/100 g gelatin and 0, 5, 10 and 15 g MMT/100 g gelatin. Rheological tests were carried out in an AR2000 rheometer. Also, the dispersions of MMT in water were analyzed to determine the pH, the mean diameter, and the ζ-potential. The MMT concentration affected significantly the mean diameter of the dispersed nanoparticles, but only affected the ζ-potential for the 5% gelatin system. The MMT dispersions presented Newtonian behavior with low viscosity. The NFS presented viscoelastic behavior. The sol–gel and gel–sol transition temperatures were affected by the MMT concentration. Moreover, the NFS in the sol domain presented a non-Newtonian behavior affected by the MMT concentration.