Interfacial Properties Of Suspended Particles

• Interfacial Properties of Suspended Particles are key in drug formulation, emulsions, and colloidal systems.
• Interfacial Properties of Suspended Particles influence, aggregation, and dispersion in suspensions.
• At the interface between suspended particles and the surrounding liquid, several key properties affect the behavior and stability of the suspension:

1. Interfacial Tension

   • Exists between the solid particle surface and the liquid.
   • Higher tension = more energy, promoting aggregation unless stabilized.

2. Wettability

   • Measured by the contact angle between the solid and liquid.
     • Hydrophilic particles: well-wetted → stable dispersion.
     • Hydrophobic particles: poorly wetted → aggregation.

3. Zeta Potential

   • Reflects the electrostatic potential at the particle’s slipping plane.
   • A high absolute zeta potential (> ±30 mV) indicates strong repulsion → stability.
   • Low zeta potential → particles come closer → flocculation/aggregation.

4. Stabilization

   • Electrostatic stabilization: Charged particles repel each other.
   • Steric stabilization: Surfactants or polymers form barriers around particles.

Why Interfacial Properties Matter:

• Pharmaceuticals: affect drug suspension stability
• Paints/Coatings: influence sedimentation and uniformity
• Food emulsions: stability of suspended particles (e.g. cocoa in chocolate milk)
• Environmental science: transport of particulates in water

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