Reply to "Comment on 'Long-range electrostatic interactions between like-charged colloids: Steric and confinement effects' " - art. no. 043401

In his Comment to [Phys. Rev. E 60, 6530 (1999)], Mateescu shows that while the effective interactions remain repulsive when the specific size of the microions is taken into account via a Modified Poisson-Boltzmann equation, a similar conclusion cannot be reached for the situation of complete latera l confinement. This point is correct but has already been considered in a m ore general study [Phys. Rev. E 62, R 1465 (2000). where repulsion is gener ically obtained]; moreover, we argue that it illustrates the irrelevancy of the notion of pair potential in completely confined configurations, as sho wn in a simple example.