The depletion potential between two colloid particles immersed in a hydrogen bonding fluid has been investigated by density functional theory. The study is motivated by the wide applications of hydrogen bonding fluids in the field of colloid science, and the effects of relevant factors on the depletion potential and depletion force between colloid particles have been studied. These factors include the size ratio of the colloid particle to the fluid molecule, the bulk density of the fluid, the functionality (the number of proton acceptors a and proton donors d) and hydrogen bonding strength as well as the colloid-fluid interaction energy. By comparing the depletion potential calculated under various conditions, it is shown that the effects of these factors on the depletion potential are very significant, and in particular in regulating the depletion force and its range.
