Plgel mixed guard column

Size exclusion chromatography (SEC) experiments were performed on an Agilent 1200 series HPLC system equipped with an Agilent PLgel mixed guard column (particle size = 5 µm) and two Agilent PLgel mixed-D columns (ID = 7.5 mm, L = 300 mm, particle size = 5 µm). Signals were recorded by a UV detector (Agilent 1200 series), an Optilab REX interferometric refractometer, and a miniDawn TREOS light scattering detector (Wyatt Technology Corp.). Samples were run using THF as the eluent at 30 °C and a flow rate of 1.0 mL/min. Data analyses were carried out on Astra software (Wyatt Technology Corp.) and molecular weights were determined based on narrow molecular weight poly(styrene) standards. Polymer 2 had a Mn = 6,700 g/mol , weight-average molecular weight (Mw) = 13,000 g/mol, dispersity (Ð) = 1.95. (see Supporting Information, Figure S6). The relatively high dispersity is common for atom transfer radical polymerization (ATRP) of OEG3A monomers without the introduction of CuX2 deactivator species. 47 (link) The deprotected POEG3A had a Mn = 5,100 g/mol, Mw = 10,000 g/mol, Ð = 1.95 (see Supporting Information, Figure S5 -S6, Table S1). However, in this article, the Mn of 17,700 g/mol determined by NMR is quoted, as this method gives a more accurate estimate of the molecular weight, than SEC with a polystyrene standard.