Failure of debye-hückel screening in low-charge colloidal suspensions

Abstract

Derjaguin–Landau–Verwey–Overbeek (DLVO) theory remains the cornerstone of colloid stability. Electrostatic interactions dominate van der Waals attractions at large colloid-colloid separations h, unless strongly screened. Under these conditions, the potential U(h) between charged colloids is expected to be exponentially screened, U(h) ∼ exp(−κh)/h, with κ−1 = λD where λD is the classical Debye-Hückel screening length. By measuring the force between individual charged particles at dilute electrolyte concentrations (