DLVO

The DLVO (Derjaguin-Landau-Verwey-Overbeek) potential combines electrostatic repulsion with van der Waals attraction to model colloidal interactions in aqueous solutions. It is the sum of a repulsive electrostatic term (Debye-Hückel) and an attractive van der Waals term (typically modeled as a Lennard-Jones potential).

\[U_{DLVO} = U_{DH} + U_{LJ}\]

where:

• \(U_{DH}\) is the Debye-Hückel potential

• \(U_{LJ}\) is the Lennard-Jones potential

The Debye-Hückel term is given by:

\[U_{DH} = \frac{q_i q_j}{4\pi\epsilon_0\epsilon_r} \frac{e^{-r/\lambda_D}}{r}\]

The Lennard-Jones term can be any of the three types (Type1, Type2, or Type3) as described in the LennardJones potential documentation.

---

• type: NonBonded, DLVOType1 (or DLVOType2 or DLVOType3)

• parameters:

  • cutOffNPFactor: real: Interaction range for LJ as a multiple of sigma

  • cutOffDHFactor: real: Interaction range for DH as a multiple of the Debye length

  • dielectricConstant: real: Relative permittivity of the medium \(\epsilon_r\)

  • debyeLength: real: Debye length \(\lambda_D\) \([distance]\)

• data:

  • name_i: string: Type of particle i

  • name_j: string: Type of particle j

  • epsilon: real: LJ potential well depth \([energy]\)

  • sigma: real: LJ zero-potential distance \([distance]\)

Example:

"dlvo":{
  "type":["NonBonded","DLVOType1"],
  "parameters":{
    "cutOffNPFactor":2.5,
    "cutOffDHFactor":3.0,
    "dielectricConstant":78.5,
    "debyeLength":1.0,
    "condition":"all"
  },
  "labels":["name_i", "name_j", "epsilon", "sigma"],
  "data":[
    ["A", "A", 1.0, 1.0],
    ["A", "B", 1.2, 0.9],
    ["B", "B", 0.8, 1.1]
  ]
}

Note

The DLVO potential uses the charge and radius information stored in the particle data. Ensure that these properties are properly set for each particle before using this potential.

Warning

The DLVO theory has limitations and may not accurately describe all colloidal systems, especially at short distances or in highly concentrated solutions.