Synthesis of a thermosensitive polycation by random copolymerization of N-vinylformamide and N-vinylbutyramide

Abstract

The novel thermoresponsive polycations poly(N-vinylbutyramide-co-vinylamide) (poly(NVBA-co-VAm)), with different mole ratios of poly(VAm) (PVAm):poly(NVBA) (PNVBA), were synthesized as a biomaterial by free radical copolymerization of poly (N-vinylbutyramide-coN -vinylformamide) (poly(NVBA-co-NVF), followed by acid hydrolysis. Such poly(N-vinylamide)s do not generate toxic low-molecular-weight amine compounds by hydrolysis, although the poly(acrylamide) structural isomers do. The mole ratio of PVAm and PNVBA was varied by adjusting the NVF:NVBA mol% feeding ratio used in the copolymerization. The lower critical solution temperature (LCST) of the obtained copolymers was investigated and compared with that of PNVBA. PNVBA showed an LCST of 32 1C, while that for poly(NVBA-co-VAm) increased as the VAm mole ratio increased (due to the increasing hydrophilicity), and the more physiologically relevant temperature (for humans) of 36.5 1C was obtained at a VAm mole ratio of 5%. Furthermore, the LCST of these copolymers not only depended on the VAm mole ratios but also on the pH, the concentration of the copolymer solution and ionic strength. Variation in the copolymer LCST could lead to several applications, especially for copolymers with an LCST value around physiological temperature that would potentially be of merit for a controlled drug or biomolecule delivery system.

Radical Copolymerization of N‐Vinylformamide with Methylvinylketone: An Approach to Iminium/Imine Ring Containing Polymers

“…Numerous publications clearly indicate the excellent copolymerization abilities of NVF . The copolymerization of NVF with vinyl monomers possessing electron deficient CC double bonds such as acrylates, acrylamides, or maleates yields copolymers with alternating tendencies, while copolymerization with ethylene or vinyl esters forms random types of copolymers .…”

Thermal- and pH-Dependent Size Variable Radical Nanoparticles and Its Water Proton Relaxivity for Metal-Free MRI Functional Contrast Agents

“…Separately, we reported that water-soluble supra-molecules consisting of urea benzene frameworks (UBDs) having oligoethylene glycol chains (OEGs) showed thermal responsiveness in water solution (Figure ). Upon heating the solution, an abrupt self-assemble behavior with low temperature critical temperature (LCST) took place due to the dehydration surrounding OEGs, forming microsize particles. This LCST property is rare for supra-molecules .…”