1H Nuclear Magnetic Resonance (NMR) Spectroscopy. All NMR spectra were recorded using on a Bruker Avance III 400 MHz spectrometer using an external lock and referenced to the residual nondeuterated solvent. Chemical shifts (δH) are reported in parts per million (ppm).
Size Exclusion Chromatography (SEC). SEC analyses of polymer samples were performed using a Shimadzu modular system comprising a DGU-20A3R degasser unit, an SIL-20A HT autosampler, a 10.0 μm bead-size guard column (50 × 7.8 mm) followed by three KF-805L columns (300 × 8 mm, bead size: 10 μm, pore size maximum: 5000 Å), a SPD-20A UV/Vis detector, and an RID-10A differential refractive-index detector. The temperature of columns was maintained at 40°C using a CTO-20A oven. The eluent was dimethylacetamide (CHROMASOLV Plus for HPLC) and the flow rate was kept at 1.0 mL/min using a LC-20AD pump. A molecular weight calibration curve was produced using commercial narrow molecular weight distribution polystyrene standards with molecular weights ranging from 500 to 2 × 106 g/mol. Polymer solutions at approx. 2 mg/mL were prepared and filtered through 0.45 μm PTFE filters before injection.
Size Exclusion Chromatography (SEC). SEC analyses of polymer samples were performed using a Shimadzu modular system comprising a DGU-20A3R degasser unit, an SIL-20A HT autosampler, a 10.0 μm bead-size guard column (50 × 7.8 mm) followed by three KF-805L columns (300 × 8 mm, bead size: 10 μm, pore size maximum: 5000 Å), a SPD-20A UV/Vis detector, and an RID-10A differential refractive-index detector. The temperature of columns was maintained at 40°C using a CTO-20A oven. The eluent was dimethylacetamide (CHROMASOLV Plus for HPLC) and the flow rate was kept at 1.0 mL/min using a LC-20AD pump. A molecular weight calibration curve was produced using commercial narrow molecular weight distribution polystyrene standards with molecular weights ranging from 500 to 2 × 106 g/mol. Polymer solutions at approx. 2 mg/mL were prepared and filtered through 0.45 μm PTFE filters before injection.