3.5. Thermal assessment of the affinity towards aqueous
media
The antibacterial activity of MNP-loaded materials is often determined
by their affinity towards aqueous media where bacteria live. This
affinity towards water can be evaluated by TGA (Fu et al., 2015). The
TGA patterns (Fig. S11.a ) revealed a single and small weight
loss (WL) of at most 0.7-0.8% for NaMt between 20 and 120oC. This corresponds to reversible dehydration, as
shown by repeated TGA analysis of rehydrated samples. The total absence
of other weight losses and more particularly of dehydroxylation (2
-Si-OH Si-O-Si- + H2O) at higher temperature provided
evidence that NaMt is stable throughout the entire range of temperature
investigated. MNP insertion into NaMt gave rise to a marked endothermic
process at ca. 140-480 oC for
Cu0/NaMt and 90-470 oC for
Ag0/NaMt. This accounts for 6.6 % and 9.4 % WL,
respectively (Table 2 ).