Polydiallyldimethylammonium chloride (commonly abbreviated as PolyDADMAC) is a synthetic, water-soluble cationic polyelectrolyte widely used in industrial and municipal applications due to its strong positive charge and ability to interact with negatively charged particles.

🔬 Chemical Overview:

• Chemical name: Poly(diallyldimethylammonium chloride)

• CAS Number: 26062-79-3

• Monomer unit: Diallyldimethylammonium chloride (DADMAC)

• General formula: ([–CH_2–CH(CH_2–N^+(CH_3)_2–CH=CH_2)–Cl^––]_n)

• Appearance: Typically supplied as a clear, viscous aqueous solution (e.g., 10–50% active concentration), though solid forms exist.

• Charge density: Very high (fully quaternary ammonium groups → permanent positive charge, independent of pH)

🏭 Key Applications:

1. Water & Wastewater Treatment:

• Acts as a primary coagulant or flocculant aid.

• Neutralizes negative charges on colloids (e.g., clay, organic matter, microbes), enabling particle aggregation and removal via sedimentation or filtration.

• Effective at low doses; often used before anionic polymers in dual-polymer systems.

2. Paper Manufacturing:

• Retention aid: Helps retain fine fibers and fillers on the paper sheet.

• Drainage promoter: Improves dewatering on the wire section.

• Dry strength additive: Enhances paper strength.

3. Cosmetics & Personal Care:

• Used in conditioners, hair masks, and skin products for its antistatic and film-forming properties.

• Binds to negatively charged hair/skin surfaces, improving softness and manageability.

4. Other Uses:

• Sludge dewatering

• Textile processing

• Enhanced oil recovery (EOR)

• Biocidal formulations (due to quaternary ammonium structure)

✅ Advantages:

• Highly effective at low dosages

• Works over a wide pH range (charge is pH-independent)

• Rapid action in coagulation/flocculation

• Compatible with many other treatment chemicals

⚠️ Considerations:

• Can be expensive compared to inorganic coagulants (e.g., alum, ferric chloride)

• Overdosing may restabilize colloids (charge reversal)

• Requires careful handling—irritant to eyes/skin in concentrated form

In summary, PolyDADMAC is a versatile, high-performance cationic polymer essential in processes requiring charge neutralization and particle aggregation—especially where efficiency, clarity, and low sludge volume are priorities.