Sodium 4 styrene sulfonate

Sodium 4-styrene sulfonate (NaSS), phosphate buffer saline (PBS), and Mohr's salt were purchased from Sigma Aldrich. Polyethylene terephthalate (PET) (0.25 mm, biaxially oriented plate) was purchased from Goodfellow (Paris, France). Ethanol absolute was from Fisher.

Poly(ethylenimine) ( )), poly(sodium 4-styrenesulfonate) ( ), poly(allylamine hydrochloride) (
), polyvinylpyrrolidone (PVP,
), hexadecyltrimethylammonium bromide (CTAB H6269, >99.9%), hydrogen tetrachloroaurate trihydrate (HAuCl 4 •3H 2 O, >99.9%), sodium borohydride (NaBH 4 , >99%), L -ascorbic acid (>99%), silver nitrate (AgNO 3 , >99%), and glycerol were purchased from Sigma-Aldrich, sodium chloride was purchased from Carl Roth, and nitric acid (68%) was purchased from Prolabo. The silver nanowires used for Figures 1,2,4, 5, S2, S4, S5, S6, and S13 were purchased from Novarials (d ≈ 55 nm, L ≈ 23 μm). All the chemicals were used without further purification. Silicon wafers were bought from WaferNet, and quartz and glass slides from Thuet B. Ultrapure water with a resistivity of 18.2 MΩ•cm was obtained by purification with a Milli-Q gradient system (Millipore) and was used directly after production. Poly(ethylene imine) solutions were freshly prepared by direct dissolution of 2.5 mg/mL of the polymer in ultrapure water. Poly(sodium 4-styrenesulfonate) solutions were prepared in NaCl solution (0.5 M) at a concentration of 0.618 mg/mL. Poly(allylamine hydrochloride) solutions were prepared in NaCl solution (0.5 M) at a concentration of 0.285 mg/mL.