Abstract:

Polymers have interesting physicochemical characteristics such as charge density, func‐ tionalities, and molecular weight. Such attributes are of great importance for use in industrial pur‐ poses. Understanding how these characteristics are affected is still complex, but with the help of molecular dynamics (MD) and quantum calculations (QM), it is possible to understand the behavior of polymers at the molecular level with great consistency. This study was applied to polymers de‐ rived from polyacrylamide (PAM) due to its great use in various industries. The polymers studied include hydrolyzed polyacrylamide (HPAM), poly (2‐acrylamido‐2‐methylpropanesulfonate) (PAMPS), polyacrylic acid (PAA), polyethylene oxide polymer (PEO), and guar gum polysaccha‐ ride (GUAR). Each one has different attributes, which help in understanding the effects on the pol‐ymer and the medium in which it is applied along a broad spectrum. The results include the con‐ formation, diffusion, ion condensation, the structure of the water around the polymer, and intera‐ tomic polymer interactions. Such characteristics are important to selecting a polymer depending on the environment in which it is found and its purpose. The effect caused by salinity is particular to each polymer, where polymers with an explicit charge or polyelectrolytes are more susceptible to changes due to salinity, increasing their coiling and reducing their mobility in solution. This natu‐ rally reduces its ability to form polymeric bridges due to having a polymer with a smaller gyration radius. In contrast, neutral polymers are less affected in their structure, making them favorable in media with high ionic charges.

Keywords: soluble polymers; flocculation; salinity; molecular dynamic; ion adsorption