*3.4. Morphological Characterizations*

All untreated and treated cotton samples were investigated by SEM and AFM microscopy, in order to characterize the morphology of the coated textile fabric and to underline structural differences before and after the coating application.

SEM analysis shows that the two analyzed tissues have two different weaves: COH\_UT samples have a larger weave than COL\_UT ones, and the fibers appear less ordered compared with COL\_UT ones and more threadbare (compare Figure 4a,b). Both samples do not show modifications after treatment and the morphology appears unchanged also at higher magnification (Figure 5). This demonstrates that, after treatment, no changes at micrometer scale occur.

**Figure 4.** SEM analysis of investigated samples: COH\_UT (**a**), COL\_UT (**b**), COH\_GPTES (**c**), COL\_GPTES (**d**), COH\_G-PNPA (**e**), COL\_G-PNPA (**f**).

**Figure 5.** SEM analysis of investigated samples at higher magnification: COH\_UT (**a**), COL\_UT (**b**), COH\_GPTES (**c**), COL\_GPTES (**d**), COH\_G-PNPA (**e**), COL\_G-PNPA (**f**).

EDS analysis shows Si peak only in samples treated with GPTES (COH\_GPTES, COL\_GPTES) and subsequently with PNPA (COH\_G-PNPA, COL\_G-PNPA) (Figure 6, only two treated samples are reported for briefness, because the other ones exhibited a similar spectrum). The other peaks refer to carbon, present in the analyzed tissues but also in graphite adhesive used for SEM analysis, oxygen, present also in vapor-low vacuum atmosphere, and aluminum, derived from the SEM stub.

**Figure 6.** EDS analysis of investigated samples: COH\_UT (**a**), COL\_UT (**b**), COH\_G-PNPA (**c**), COL\_G-PNPA (**d**), and mapping of COH\_G-PNPA (inset **c\***) and COL\_G-PNPA (inset **d\***).

The mapping presented in Figure 6 (inset c\* and d\*) shows that distribution of Si element (present in GPTES) is very uniform and no phase separation occurs.
