Linear polystyrene calibration standards

The film samples for each timepoint were frozen at −20 °C and lyophilised. Each sample was then dissolved in THF at a concentration of 2 mg mL⁻¹ and filtered through a cotton filter prior to passing into a HPLC vial in order to remove the insoluble salts from the aqueous media used to carry out the reaction. Gel permeation chromatography was carried out at 30 °C on an Agilent Technologies HPLC System (1260 series, Agilent Technologies, Palo Alto, CA, USA) connected to a 6.0 mm ID  ×  40 mm L HHR-H, 5 μm Guard column and a 7.8 mm ID  ×  300 mm L GMHHR-N, 5 μm TSK gel liquid chromatography column (Tosoh Bioscience, Tessenderlo, Belgium) using 1 mL min⁻¹ THF as the mobile phase. An Agilent Technologies G1362A refractive index detector was employed for detection. The molecular weights of the polymers were calculated using linear polystyrene calibration standards in the 400–2,000,000 Da M_p range (Sigma-Aldrich, St. Louis, MO, USA). Data processing was carried out using the Agilent GPC/SEC software (Version 1.2, Figures S7–S10).

The samples were dissolved in CHCl₃ at a concentration of 2 mg mL⁻¹ and filtered through cotton filters. Gel permeation chromatography was carried out at 30 °C on an Agilent Technologies HPLC System (Agilent Technologies 1260 Infinity) connected to a 17,369 6.0 mm ID × 40 mm L HHR-H, 5 μm Guard column and a 18,055 7.8 mm ID × 300 mm L GMHHR-N, 5 μm TSK gel liquid chromatography column (Tosoh Bioscience, Tessenderlo, Belgium) using CHCl₃ as an eluent (at a flow rate of 1 mL min⁻¹). An Agilent Technologies G1362A refractive index detector was employed for detection. The molecular weights of the polymers were calculated using linear polystyrene calibration standards (250–70,000 Da) purchased from Sigma-Aldrich.