2414 differential refractometer

¹H NMR and ¹³C NMR spectra were recorded on a Bruker Ascend^TM-400 spectrometer, with tetramethylsilane as an internal reference. The absorption spectra were measured on a SHIMADZU/UV-2550 model UV-visible spectrophotometer. Cyclic voltammetry was performed on a BAS 100B/W electrochemical analyzer with a three-electrode cell in a 0.1N Bu₄NBF₄ solution in acetonitrile at a scan rate of 50 mV/s. The polymer film was coated onto a Pt wire electrode by dipping the electrode into a polymer solution in chloroform. All measurements were calibrated against an internal standard of ferrocene (Fc), the ionization potential (IP) value of which is −4.8 eV for the Fc/Fc + redox system. The number- and weight-average molecular weights of the polymers were determined by gel-permeation chromatography (GPC) with a Waters 2690 Associates liquid chromatography instrument equipped with a Waters 2414 differential refractometer. Chloroform was used as the eluent and polystyrene as the standard. The surface morphology of polymer films was measured by atomic force microscopy (AFM) using tapping mode, and the AFM scan images (2 μm × 2 μm) were acquired in tapping mode on a Nanoscope instrument (Bruker).

The molecular weight distribution was examined in liquid samples on a Waters size-exclusion chromatography system (Waters, Milford, MA, USA), with a Waters 600E system controller, coupled with a refractive index detector (Waters 2414 Differential Refractometer), a UV detector (Waters 486 Tunable Absorbance Detector) that was set to 234 nm, and a pump (Waters 600 gradient pump). Samples were injected using an autosampler (Waters 717 plus autosampler) with an injection volume of 20 µL. Fractionation was performed on a TSKgel column (G4000PWXL, TOSOH Bioscience GmbH, Griescheim, Germany), with deionized water as the eluent at a flow rate of 0.5 mL/min. Polyethylene glycol standards (Merck Schuchardt OHG, Germany) were used for the column calibration (100 kDa, 35 kDa, 10 kDa, 4 kDa, 400 Da).