Hierarchical self-assembly of bulk metamaterials enables isotropic magnetic permeability parameter at optical frequencies

Chemicals: Silver nitrate (AgNO3, 99.999%), sodium hydrosulfide (NaHS), L-arginine (≥ 98%), tetraethyl orthosilicate (TEOS; ≥ 90%), sodium citrate dihydrate (≥ 99%), cyclohexane (> 99.7%), poly-(vinyl-pyrrolidone) (PVP; Mw~55,000) and Acetone (CH3COCH3, ≥99.5%) were purchased from Sigma-Aldrich. Iodomethane (CH3I, 99%) was purchased from Acros Organics and N,N-Dimethylformamide (DMF, anhydrous 99.8% packaged under Argon in resealable bottle) from Alfa Aesar. Ethylene glycol (EG, 99%), ammonium hydroxide (NH4OH, 28-30 wt.%) were obtained from J.T. Baker. Absolute ethanol was purchased from Atlantic Labo. Poly(1-vinyl-1,2,4-triazole) (PVTri, MW=21,260 g/mol calculated through conversion from 1HNMR) was prepared through Reversible Addition Fragmentation Chain Transfer (RAFT) polymerization at 60°C in DMF [S1].