Polyacrylamide is a polymer with a wide range of applications, including use in wastewater treatment, gel electrophoresis, and enhanced oil recovery. Its mechanism of action depends on the specific application, but generally, polyacrylamide functions through its unique properties as a polymer.

In water treatment, polyacrylamide is often used as a flocculant. It works by attracting and binding to suspended particles and colloids present in the water. The polymer has a high molecular weight and forms long chains, which create a bridging effect between the particles, causing them to aggregate and form larger, heavier flocs. These flocs are easier to separate from the water through processes like sedimentation or filtration, allowing the removal of impurities.

In gel electrophoresis, polyacrylamide forms a matrix within which biomolecules, such as proteins or nucleic acids, can be separated based on their size and/or charge. The polyacrylamide forms a porous gel network when crosslinked, with different pore sizes determined by the concentration of the polymer and the crosslinking agents used. The biomolecules migrate through the gel matrix under the influence of an electric field, and their mobility is impeded based on their size and charge, leading to separation.

In enhanced oil recovery, polyacrylamide is used as a thickening agent or viscosity modifier to improve the flow characteristics of injected water or other fluids. It increases the viscosity of the fluid, which helps to displace the oil trapped in the reservoir and improve its recovery. The high molecular weight of polyacrylamide provides it with a high resistance to shear forces, allowing it to maintain its thickening effect under the conditions encountered in oil reservoirs.

Overall, polyacrylamide's mechanism of action relies on its ability to form long chains and provide unique physical properties, such as flocculation, gel formation, or viscosity enhancement, depending on the desired.