Trisodium citrate tsc

Hydrogen tetrachloroaurate trihydrate (HAuCl₄·3H₂O) of 99.99% purity (Alfa Aesar, Karlsruhe, Germany) and trisodium citrate (TSC) of 99.99% purity (Sigma-Aldrich, Milan, Italy) were used as received. Milli-Q water of high purity and resistivity of 18.2 MΩ·cm was used during all the AuNP synthesis, cleaning and sample preparation. Substrates of ≈4 cm² surface area were cut off of ≈1 mm thick plates of either glass from commercial optical microscope slides (Menzel-Gläser, Germany) and pure fused silica (Heraeus, Germany), called quartz in the following. Before use, the substrates were cleaned by successive sonication (5 min at each step) in warm acetone, then isopropanol, then water, and finally blown dry under a nitrogen stream. As the last step, the substrates were treated for 20 min inside a UV-ozone cleaner Procleaner (BioForceNanosciences, USA).

Viscose fibers (VF) were obtained from Lenzing, Austria. Silver nitrate (Ag NO₃) was obtained from Panreac, Barcelona, Spain. Trisodium citrate (TSC) was supplied by Sigma-Aldrich (Germany). Ethanol was obtained from Sigma-Aldrich, Germany. Titanium isopropoxide (C₁₂H₂₈O₅Ti, 97%,), 2-aminoterephthalic acid (C₈H₇NO₄, 99%), and sulfadiazine (99.0–101.0%) were obtained from Sigma-Aldrich, Germany. Sulphanilamide (BDH laboratory reagent) and sulfamethazine were obtained from Spectrum Chemical MFG Corp., England.