A periodically
precipitating system wherein interband distance
successively decreases is known as revert Liesegang banding. The phenomenon
is rare, and the underlying mechanism is implicit. In the present
paper, the Liesegang system comprising of AgNO
3
and KBr
as the outer and inner electrolyte pair showing revert banding in
agar gel by employing a 1D experimental setup is studied under varying
concentrations of participating species. Revert banding was observed
under all the experimental conditions. The concentrations of inner
and outer electrolytes were found to play a major role in reverting
since they build the ionic strength inside Liesegang tubes. We hypothesize
that the band reverting is the interplay of van der Waals and electrical
double-layer interactions, and hence classical DLVO (Derjaguin–Landau–Verwey–Overbeek)
theory can be applied to interpret reverting. We propose that revert
deposition of precipitates is the outcome of flocculation and peptization
of sols, which is the manifestation of balancing attractive and repulsive
interactions acting on colloidal particles responsible for band formation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.