Small-angle neutron scattering study of the mesostructure of bioactive coatings for stone materials based on nanodiamond-modified epoxy siloxane sols

The structure formation of sol-gel-derived epoxy siloxane compositions with different ratios of the main precursors ($R_{\mathrm{TEOS/EPONEX1510}}$ = 16/38, 27/27, 38/16 wt%) and with different concentrations of detonation synthesis nanodiamonds ($c_{\mathrm{DNA}}$ = 0.05, 0.10, 0.20 wt%) has been investigated using small-angle neutron scattering (SANS). Based on the SANS data, it has been revealed that the synthesized epoxy siloxane xerogels are systems with a two-level fractal structure, in the formation of which the siloxane component plays a dominant role. It has been found that the fractal dimension $D_{m2}$ and the radius of gyration $R_{g2}$ of clusters in the epoxy siloxane compositions decrease with an increase in the content of the siloxane component. It has been established that the introduction of small additions of detonation synthesis nanodiamonds (less than 1 wt%) into the epoxy siloxane composition with an equal ratio of the main precursors $R_{\mathrm{TEOS/EPONEX1510}}$ = 27/27 wt% leads to a transition from the two-level to three-level structure organization and affects the fractal dimension $D_m$ and the radius of gyration $R_g$ of the formed clusters.