Wyatt minidawn treos light scattering detector

In a 25 mL round-bottomed flask, ECT (0.2 mmol, 0.052 g), 2-(dimethylamino)ethyl methacrylate (DMAEMA) (25.2 mmol, 3.99 g, 4.28 mL), and AIBN (0.02 mmol, 0.0034 mg) were dissolved in 1,4-dioxane (5 mL) (Figure S2A). The reaction mixture was degassed by purging nitrogen through the solution for 30 min and submerged into a preheated oil bath at 70 °C for 24 h. After 24 h, the polymerization mixture was precipitated into a 10-fold excess of cold pentane and dried under vacuum overnight. The structure of PDMAEMA was characterized by ¹H nuclear magnetic resonance spectroscopy (Figure S2B) NMR, 400 Bruker Spectrophotometer) in CDCl₃ solvent. The molecular weight and polydispersity of the polymer was characterized by gel permeation chromatography (GPC, Agilent Technologies, Santa Clara, CA) in dimethylformamide (DMF) + 0.1 M LiBr with inline Agilent refractive index and Wyatt miniDAWN TREOS light scattering detectors (Wyatt Technology Corp., Santa Barbara, CA). M_n,_GPC = 10 500, PDI = 1.15 (Figure S2C).

RAFT polymerization was used to synthesize a 50:50 [BMA]:[DMAEMA] copolymer using the PEG-ECT macro-CTA. The target degree of polymerization was 160, and the monomer plus CTA was 40% weight per volume in dioxane. The polymerization reaction was carried out at 70°C for 24 hours using AIBN as the initiator with a 5:1 [CTA]:[Initiator] molar ratio. A monomer feed ratio of 50:50 mol % or 0:100 mol % [BMA]:[DMAEMA] was used (to generate 50B and 0B respectively), and a double alumna column was utilized to remove inhibitors from DMAEMA and BMA monomers prior to polymerization. The reactions were stopped by removal from heat and exposure of the polymerization solution to air. The resulting polymers were precipitated into a co-solvent of 90% pentane and 10% diethyl ether. The isolated polymers were vacuum-dried, redissolved in water, further purified by dialysis for 24 hours, and lyophilized. Polymers were characterized for composition and molecular weight by ¹H-NMR spectroscopy (Bruker 400 MHz spectrometer equipped with a 9.4 T Oxford magnet). Absolute molecular weight and polydispersity of the polymers was determined using DMF mobile phase gel permeation chromatography (GPC, Agilent Technologies, Santa Clara, CA, USA) with inline Agilent refractive index and Wyatt miniDAWN TREOS light scattering detectors (Wyatt Technology Corp., Santa Barabara, CA, USA).

A library of rhodamine-containing PEG-DB polymers ranging from 20 mol % B to 70 mol % B (20B–70B) was synthesized via RAFT polymerization. Monomers were dissolved in a 10% N,N-dimethylformamide (DMF)/90% dioxane solution (mass of monomer + CTA equal to 20% of total mass) and reacted for 24 h under nitrogen atmosphere at 35 °C. The reaction was prepared such that 100% monomer conversion would achieve a degree of polymerization of 200. The radical initiator 2,2′-azobis(4-methoxy-2,4-dimethyl valero nitrile) (V-70) was added to the reaction at a 1:5 V-70 initiator to CTA molar ratio. Following 24 h, the resulting polymers were dialyzed against methanol in dialysis tubing with a 12k–14k molecular weight (MW) cutoff to remove unreacted monomers and residual solvent. Dialysis was then completed against deionized (DI) water to remove methanol, after which the polymers were frozen and lyophilized. Polymers were characterized for composition and MW by ¹H NMR spectroscopy (Bruker 400 MHz spectrometer equipped with 9.4 T Oxford magnet). The absolute MW of the polymers was determined using DMF mobile phase gel permeation chromatography (GPC, Agilent Technologies, Santa Clara, CA, USA) with inline Agilent refractive index and Wyatt miniDAWN TREOS light scattering detectors (Wyatt Technology Corp., Santa Barbara, CA).