1 methyl 2 pyrrolidone

PVDF [KF1100; M_n = 168.8 kDa, polydispersity index (PDI) = 2.94] was purchased from Kureha. tert-Butyl acrylate (tBA) was purchased from Sigma-Aldrich and was passed through an aluminum oxide column to remove the inhibitor before use. Copper(I) chloride (CuCl, 99.999%) and 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA) were purchased from Alfa Aesar. 1-Methyl-2-pyrrolidone (NMP) was purchased from JUNSEI. All solvents were reagent grade, and all reagents were used as received. The molecular mass of PVDF and graft copolymers were measured by gel permeation chromatography (GPC) conducted at 23°C in N,N′-dimethylformamide (DMF) at a flow rate of 1 ml/min, using an Agilent 1260 Infinity GPC system equipped with a PLgel 5 μm Mixed B column (Polymer Laboratories) and differential refractive index detectors. Monodisperse PS standard (Polymer Laboratories) was used for calibration. ¹H NMR was performed in deuterated DMF, using a 400-MR DD2 (Agilent) 400-MHz spectrometer. The FTIR spectra were recorded on a 670-IR (Agilent) spectrophotometer.

1,2-Phenylenediamine (99.5%), phosphorous pentoxide (99%), vanadium(iv) oxide sulfate hydrate (97%), vanadium(v) oxide (99.6%), and dimethylformamide (DMF) were obtained from Aldrich. 3,3′-Diaminobenzidine (DABI, 98%) and trimellitic anhydride (4-carboxyphthalic anhydride, 98%) were acquired by TCI. Polyphosphoric acid (PPA, 116%) and 1-methyl-2-pyrrolidone (NMP) were purchased from Junsei Chemical. Sulfuric acid (95–97%) was provided by Merck. Sodium bicarbonate, methanol, dimethyl sulfoxide (DMSO) were provided by Samchun Chemical, Korea. Nafion 115 and Nafion ionomer (D1021) were supplied by Dupont. All of the reagents and solvents above were handled without purification.