The Electric Double Layer

  • Development of a nett charge at the particle surface affects the distribution of ions in the surrounding interfacial region, resulting in an increased concentration of counter ions (ions of opposite charge to that of the particle) close to the surface
  • Thus an electrical double layer exists round each particle
  • An electrical double layer exists around each particle. 
  • The liquid layer surrounding the particle exists as two parts; an inner region (Stern layer) where the ions are strongly bound and an outer (diffuse) region where they are less firmly associated
  • Within this diffuse layer is a notional boundary known as the slipping plane, within which the particle acts as a single entity
  • The potential at this boundary is known as the Zeta Potential

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