Fig. 3

FE-SEM top-view micrographs showing different magnifications of the tested sample sets on different substrates. The micrographs illustrate the differences in nanofiller distribution and exposition over the adhesive surface (GNPs are pointed out by the white arrows and dotted frames): a, e, i represent the control adhesive on different substrates ( p₀, p₂₀ and p₁₅₀). GNPs are embedded in correspondence of the p₀ substrate (b–d); the nanofillers are well dispersed and exposed over the surface of adhesives filled with at 0.1 and 0.2%wt, applied on the substrates p₂₀ and p₁₅₀ (f, g, l, m); GNPs are exposed over the surface of the adhesive filled with at 0.5%wt, more densely when applied over the substrate with larger porosity p₁₅₀ (n) than over the substrated with smaller porosity p₂₀ (h). Scale bar 1 µm