Bioengineering functional copolymers:: V.: Synthesis, LCST, and thermal behavior of poly(N-isopropyl acrylamide-co-p-vinylphenylboronic acid)

New boron-containing stimuli-responsive (pH- and temperature-sensitive) copolymers were synthesized and characterized. Structure and composition of copolymers were determined by FTIR and H-1-NMR spectroscopy, and elemental analysis and titration (N and B contents for NIPA and VPBA unit, respectively). By DSC and XRD measurements, it is established that the synthesized copolymers have a semicrystalline structure due to formation of intra- and/or intermolecular H-bonded supramolecular architecture. The copolymer composition-structure-property relationship indicates semicrystalline structure of copolymers with different compositions, degrees of crystallinity, and thermal and stimuli-responsive behaviors depends on the content of boron-containing monomer linkage. Results of DSC, DTA, and TGA analyses indicated that copolymers have T-g and T-m and high thermal stability. These water-soluble and temperature- and pH-sensitive amphiphilic copolymers can be used as polymeric carries for delivery of biological entities for diverse biomedical use, including boron neutron capture therapy. (C) 2004 Wiley Periodicals, Inc.