Vinyl phenylboronic acid controlling co‐monomer for nitroxide mediated synthesis of thermoresponsive poly(2‐N morpholinoethyl methacrylate)

Low concentrations of 4‐vinylphenylboronic acid (VPBA) were copolymerized with 2‐N‐morpholinoethyl methacrylate (MEMA) by nitroxide mediated polymerization using BlocBuilder? unimolecular initiator at 80 to 90 °C. The MEMA/VPBA copolymerizations were performed at initial feed compositions (f_VPBA,0) of 0.05 to 0.10 VPBA, with f_VPBA,0 = 0.10 using dimethylacetamide (DMAc) solvent being most effective, as seen by a linear increase in number average molecular weight, M_n, versus conversion and low dispersity, ? < 1.40. The copolymers were further chain‐extended with a second batch of VPBA, resulting in a block copolymer with monomodal molecular weight distribution and ? = 1.66. For MEMA/VPBA copolymers, increases in VPBA composition and polymer solution concentration resulted in decreases in the cloud point temperature (CPT, typically varied between 27.4–37.8 °C) and CPT increased from 31.2 to 33.8 °C to about 88 °C with decreases in pH from 7 to 4. Rheological tests with small angle light scattering (SALS) confirmed CPTs measured by UV‐Vis and DLS. These copolymers were targeted as models to combine possible glucose‐sensing boronic acid functionality the thermoresponsiveness provided by MEMA groups. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1560–1572