Helmholtz double layer

Helmholtz double layer

[′helm‚hōlts ¦dəb·əl ′lā·ər]
(physics)
An electrical double layer of positive and negative charges one molecule thick which occurs at a surface where two bodies of different materials are in contact, or at the surface of a metal or other substance capable of existing in solution as ions and immersed in a dissociating solvent.