*2.1. Materials*

Polyacrylonitrile (PAN, M<sup>w</sup> = 1.5 × 10<sup>5</sup> g/mol) was purchased from Sigma-Aldrich (St. Louis, MO, USA). Nylon 6,6 (NYL, Zytel® E53 NC010) was kindly provided by DuPont (Wilmington, DE, USA). Dimethylformamide (DMF), formic acid (FA) and chloroform (CLF), HAuCl4, PdCl2, glucose, NaOH and polyvinylpyrrolidone (PVP) were purchased from Sigma Aldrich and were used without further purification. HMF (purity > 99%) was purchased from AVABiochem (Muttenz, Switzerland) and used without any purification.
