Gpc system

Pluronic F127 (MW = 12,600, 70% PEG, composition confirmed with proton (¹H) nuclear magnetic resonance (NMR) spectroscopy), allyl bromide, sodium hydride, 2,2′-Azobis(2-methylpropionitrile) (AIBN), thioacetic acid (purum, ≥ 95.0% (GC)), Tetronic 701 (MW = 3600, 10% PEG), acryloyl chloride (purity: 97.0%, contains <210 ppm MEHQ as stabilizer), triethylamine (purity ≥ 99.5%), tris(2-carboxyethyl)phosphine hydrochloride (TCEP) (purity 98%), sodium hydroxide (purity ≥ 97%, pellets), hydrochloric acid (37%), potassium phosphate monobasic, sodium phosphate dibasic, toluene, N,N-Dimethylformamide, ammonium persulfate (APS), tetramethylethyldiamine (TEMED), and ibuprofen (purity 98%) were purchased from Merck (Sigma-Aldrich, Milan, IT, USA) and used as received.
All the functionalized polymers obtained were characterized using a 400 MHz Bruker ¹H NMR spectrometer and a Thermo Scientific Nicolet iS50 Fourier-transform infrared (FT-IR) spectrometer in Attenuated total reflection (ATR) mode. Dynamic light scattering (DLS) measurements were carried out with Malvern Zetasizer ZS (Malvern, UK). Size Exclusion Chromatography (SEC) analysis was performed with the Jasco GPC System in tetrahydrofuran (THF) at a flow rate of 1 mL/min at 35 °C, calibrated using polystyrene standards.

Several p(DMAPS-ran-PEGMA) samples were prepared by reversible addition fragmentation transfer (RAFT) copolymerization of PEGMA and DMAPS following a procedure adapted from a previous publication^{25 (link)}. Suitable amounts of the two monomers (total concentration: 0.1 mol/L), 2-(1-isobutyl) sulfanylthiocarbonylsulfanyl-2-methyl propionic acid, and VA-061 were dissolved in H₂O/methanol (2/1, v/v). The mixture was purged with N₂ for 30 min at room temperature. It was brought to 60 °C to induce polymerization and kept at this temperature for 20 to 40 h. The mixture was cooled to 4 °C to stop the polymerization. The polymerization mixture was purified by dialysis against water for 7 days (MWCO = 3,500 g/mol). The polymer was recovered by freeze-drying. Its composition was determined from the ¹H NMR spectra of the polymers dissolved in D₂O containing NaCl (1 M) using an ECA-600 spectrometer (JASCO Co. Tokyo, Japan). The molecular weights of the polymers were determined by gel permeation chromatography (GPC) with a JASCO GPC system equipped with TSKgel G3000PW_XL and G4000PW_XL columns (Tosoh Co. Tokyo, Japan) eluted with aqueous NaNO₃ (100 mM) and calibrated with PEG standards.