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 ).