Fluorescent, Thermoresponsive Oligo(ethylene glycol) Methacrylate/9-(4-Vinylbenzyl)-9H-carbazole Copolymers Designed with Multiple LCSTs via Nitroxide Mediated Controlled Radical Polymerization

9-(4-Vinylbenzyl)-9H-carbazole (VBK) was used as the controlling comonomer for nitroxide mediated polymerization with 10 mol % SG1 free nitroxide relative to Bloc Builder initiator at 80 degrees C of oligo(ethylene glycol) methyl ether methacrylate (8-9 ethylene glycol (EG) units) (OEGMA(8-9)), 2-(2-methoxyethoxy)ethyl methacrylate (MEO(2)MA) and for an OEGMA(8-9)/MEO(2)MA-mixed feed. The synthesis of MEO(2)MA/VBK and OEGMA(8-9)/VBK copolymers and MEO(2)MA/OEGMA(8-9)/VBK terpolymers exhibited linear increases in number-average molecular weight ((M) over bar (n)) versus conversion X, up until X = 0.6, with final copolymers characterized by relatively narrow, monomodal molecular weight distributions ((M ) over bar (w)/(M) over bar (n) < 1.4, in most cases). A series of MEO(2)MA/OEGMA(8-9)/VBK terpolymers were synthesized and by varying the OEGMA(8-9):MEO2MA feed ratios, the terpolymers exhibited tunable lower critical solution temperatures in water (28 degrees C < LCSTs < 81 degrees C). MEO(2)MA/OEGMA(8-9)/VBK terpolymers were deemed sufficiently pseudo-living to reinitiate a second batch of MEO(2)MA/OEGMA(8-9)/VBK, with few apparent dead chains, as indicated by the monomodal shift in the GPC chromatograms. The resulting MEO(2)MA/OEGMA(8-9)/VBK block copolymers were designed so that each block exhibited a distinct LCST, which was confirmed by UV-vis and dynamic light scattering. In addition to controlling the terpolymerization, the VBK units imparted thermo-responsive fluorescence into the final copolymers.