the range of 12.5bRb20 nm and a significant monodisperse population
of small NPs in the silver glass case with an average radius of
R≈2 nm. XRD confirms the presence of silver and copper crystallites
but lower than the NPs size. We suggest that an oxidizing layer has to
be considered in both cases. These results reveal the difficulty to initiate
the precipitation in copper NPs in comparison with silver (see
Eq. (8)). The size of the NPs is a consequence of the concentration
gradient formed around the amount of initials Ag0 or Cu0. The infrared
analysis has revealed the existence of Ag-O or Cu-O bonds after
staining. All the noble metal has not precipitated in NPs after this
thermal condition. This new information suggests that an average
maximal fill factor evaluation is the most appropriate for a future
optical estimate: SEM analyses have given fAg=0.5% and fCu=3% respectively
for silver and copper fill factors associated to their middle
thickness lAg=8 μm and lCu=10 μm. the infrared measurement has
revealed a clear trend towards the depolymerization of the silicate
network after staining. This depolymerization comes from the several
steps but not necessarily from ionic exchange: