Role of hydrogen bond interactions in water–polyol medium in the thickening behavior of cornstarch suspensions

Rheological properties of suspensions are influenced by changes in the particle’s or suspending medium’s traits. Due to the ability of water and cornstarch to develop strong hydrogen bonds with each other and with hydroxyl groups of other liquids, it is promising to modify the suspending media with polyols to analyze the change in the Newtonian behavior of the suspensions. Cornstarch–water suspensions were prepared by adding different polyols viz.., glycerine, ethylene glycol (EG), and polyethylene glycol (PEG) to the suspending liquid (water) at various concentrations. The presence of possible chemical interaction due to the hydroxyl groups within the water–polyol systems was confirmed by Fourier transfer infrared spectroscopy (FTIR). The rheological parameters of pure cornstarch–water suspension were compared with that of water–polyol-based shear thickening fluids (STFs). The thickening behavior enhanced by three orders of magnitude with increasing glycerine and EG content for a constant particle concentration. However, the presence of PEG in the suspension resulted in a shear thinning phenomenon with a high yield stress unlike the other polyols. Thus, the presence of O–H interactions in the suspending liquid was presumed to control the flow phenomenon of these suspensions. A possible mechanism based on interactions has been proposed for the non-Newtonian flow in each suspension. The current work is one of a kind in demonstrating the role of hydrogen interactions within suspending medium on the thickening behavior of the cornstarch–water suspensions.