Sodium nitrite

10,12-Pentacosadiynoic acid (PCDA) was purchased from GFS Chemicals (Ohio, USA). Lithium aluminum hydride (LiAlH₄), tetrabromomethane, triphenylphosphine, potassium iodide, and 4-dimethylaminopyridine (DMAP) were purchased from Sigma-Aldrich. N-(3-Dimethylaminopropyl)-N’-ethylcarbodiimide hydrochloride (EDC) was purchased from TCI chemicals (Tokyo, Japan). Potassium carbonate, sodium hydroxide, and sodium nitrite were purchased from Daejung Chemicals & Metals (Seoul, South Korea). Hydrochloric acid and methyl-4-aminobenzoate were purchased from Fisher Scientific (Massachusetts, USA). The detailed synthetic protocols for DA-Azo-TEG and spectral data are provided in Supporting Information.

Acid-treated natural expandable graphite (grade 1721) was purchased from Asbury Carbons, Asbury, NJ, USA. Concentrated sulfuric acid (H₂SO₄), potassium permanganate (KMnO₄), sodium nitrate (NaNO₃), sodium nitrite (NaNO₂), sodium carbonate (Na₂CO₃), hydrochloric acid (HCl, 35%), hydrogen peroxide (H₂O₂, 30 wt.%), N,N′-dimethylformamide (DMF), MMA, 2-chloroethanol, p-aminobenzoic acid, and 2,2',2"-trihydroxy-triethylamine (triethanolamine) were purchased from Daejung Reagents & Chemicals, Ulsan, Korea. Cuprous bromide (CuBr), N,N,N′,N″,N″-PMDETA and polystyrene standards for gel permeation chromatography (GPC) were purchased from Sigma-Aldrich, St. Louis, MO, USA and were used as received without further purification. The stabilizing agent was removed from commercial MMA by washing three times with sodium hydroxide (NaOH), followed by vacuum distillation; the middle portion was stored at 0°C to 4°C until use. DMF was stirred with anhydrous calcium hydride (CaH₂) and then distilled before use.