Insight into acrylate copolymer dispersion with multiple interactions using large-amplitude oscillation shear

Abstract

The rheological behavior of hydroxyethyl acrylate sodium/acryloyldimethyl taurate copolymer aqueous dispersions with multiple interactions (hydrogen-bonding, van der Waals and electrostatic interactions) is investigated. An abnormal large-amplitude oscillation shear performance is observed, i.e., the linear viscoelastic region shortens with an increase in concentration, whereas the weak-strain overshoot moves to a high strain region. The synergistic effect of the three interactions facilitates the hydrophobic interaction and the formation of strong and enough clusters. Both the entire transient network structure relaxation and cluster relaxation (deformation, rupture, recovery, and friction) play vital roles in this unique response. Significant cluster relaxation is believed to have led to the abnormal weak-strain overshoot. The experimental results are similar to those derived from an anticipation based on friction dissipation of blobs inside clusters, which implies that the weak-strain overshoot exactly stems from the clusters relaxing and the associated energy dissipation. The mechanism proposed here offers an innovative analytical technique for complex biological fluids.