Forces acting on dielectric colloidal spheres at a water/nonpolar-fluid interface in an external electric field. 1. Uncharged particles

- The external field polarizes the uncharged particles at the fluid interface.
- The particle electric field is found by using the Mehler-Fock integral transform.
- The vertical electric force on the particle can be directed upward or downward.
- The horizontal interparticle repulsion is dipolar and contact-angle dependent.
- At given angle, the dipole moment is zero; the repulsion is short-range octupolar.