Polyacrylamide (PAM) is a polymer commonly used in various fields such as water treatment, soil stabilization, and petroleum extraction. Its working principle is based on its molecular structure and chemical properties.

In water treatment, PAM primarily functions to coagulate and precipitate suspended particles such as silt, organic matter, and microorganisms. Its working principle can be broken down into several steps:

1. Adsorption: PAM molecules in water adsorb onto the surface of suspended particles through various forces like hydrogen bonding and van der Waals forces, forming charged complexes.

2. Neutralization: With abundant carboxyl (-COOH) and amine (-NH2) groups, PAM can adsorb and neutralize the charged particles in water, reducing the repulsive forces between them and facilitating their aggregation into larger clusters.

3. Bridging: Interactions between PAM molecules create bridges between suspended particles, promoting their association and the formation of larger aggregates.

4. Precipitation: Through the aforementioned processes, suspended particles are gathered into larger precipitates, which can then be separated from the water through filtration or sedimentation.

In soil stabilization and petroleum extraction, the working principle of polyacrylamide involves similar mechanisms, primarily focusing on improving soil structure or enhancing the efficiency of oil-water separation through its adsorption and coagulation properties.