Reduction of the zeta potential value of the released AgNP would result in
decreased colloidal stability, and culminate in particle
agglomeration. However, because the AgNP released
by the NRL–AgNp membranes are well-dispersed and
stable in shape and size and, as evidenced by the UV–
Vis spectroscopy, DLS technique, and TEM images,
their lower zeta potential indicates that the released
nanoparticles are also stabilized by steric repulsion. In
other word, it is possible that some molecules from the
NRL are attached to the nanoparticles surfaces,
avoiding their agglomeration when they have reduced
zeta potential.