page_title: Emulsion stabilization using polyelectrolytes
section_title: Emulsion Stability
hierarchical_section_title: Emulsion stabilization using polyelectrolytes / Emulsion Stability
caption_attribution_description: English: emulsion stability
context_page_description: Polyelectrolytes are charged polymers capable of stabilizing colloidal emulsions through electrostatic interactions. Their effectiveness can be dependent on molecular weight, pH, solvent polarity, ionic strength, and the hydrophilic-lipophilic balance. Stabilized emulsions are useful in many industrial processes, including deflocculation, drug delivery, petroleum waste treatment, and food technology.
context_section_description: When there is less interfacial tension between the polyelectrolyte particles and the emulsions in question, emulsions are less stable.  This is because the polyelectrolyte particles penetrate the flocs in suspension less when there is less interfacial tension.
  Polyelectrolytes adsorb to the interface the emulsion and help stabilize it, but may or may not lower the interfacial tension. This means that the oil or water droplets will not coalesce.
  On their own, hydrophobic surfactants cannot stabilize an emulsion.  Although they are attracted to oil, and an oil-in-water emulsion forms, the emulsion will not stay stable for long and will eventually coalesce. With the addition of a polyelectrolyte, electrostatic forces between the oil and water interface are formed and the surfactant begins to act as an “anchor” for the polyelectrolyte, stabilizing the emulsion. In addition to surfactants, nanoparticles can also help stabilize the emulsion by also providing a charged interface for the polyelectrolyte to adsorb on.
caption: Schematic representation of flocculation mechanism in SDS-stabilized (top) and surfactant-free (bottom) emulsions.
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