Characteristics and influencing factors of interaction between hydrophobic surface and drag-reducing polymer: A MC and MD simulation study

Abstract

Hydrophobic surfaces and polymer additives are both desirable for effectively reducing drag when carrying fluids, and the synergy of these two has naturally attracted a great deal of attention. The interaction between a polyurethane surface with different raw material compositions and drag-reducing polymers such as polyacrylamide (PAM), polyethylene oxide (PEO), xanthan gum (XG), and guar gum (GG) was investigated using molecular simulation methods such as molecular dynamics and Monte Carlo. The effects of polymerization degree (DP), temperature, and water molecule adsorption on the interaction were further examined. The findings demonstrate that rigid polymers (XG and GG) have a higher capacity for adsorption on the polyurethane surface than do flexible polymers (PAM and PEO). Furthermore, the DP clearly affects the PEO interacts with surfaces. Under a fixed water molecule load, the influence of surface type on water molecule adsorption ability is greater than that of polymer type but weaker than that of DP. Temperature clearly influences the interaction of PAM and surfaces, whereas PEO has the opposite effect. Additionally, PEO's deformation energy contributes more to the adsorption energy than others, whereas PAM's adsorption energy is higher because its longer molecular chains occupy the adsorption site on the surface.