Polyacrylamide-Based Block Copolymer Bearing Pyridine Groups Shows Unexpected Salt-Induced LCST Behavior

Abstract

Thermal-responsive block copolymers are a special type of macromolecule that exhibit a wide range of applications in various fields. In this contribution, we report a new type of polyacrylamide-based block copolymer bearing pyridine groups of polyethylene glycol-block-poly(N-(2-methylpyridine)-acrylamide; Px) that display distinct salt-induced lower critical solution temperature (LCST) behavior. Unexpectedly, the phase-transition mechanism of the salt-induced LCST behavior of Px block copolymers is different from that of the reported LCST-featured analogues. Moreover, their thermo-responsive behavior can be significantly regulated by several parameters such as salt species and concentration, urea, polymerization degree, polymer concentration and pH values. This unique thermal behavior of pyridine-containing block copolymers provides a new avenue for the fabrication of smart polymer materials with potential applications in biomedicine.

Synthesis of Pyridine Dicarboxylic Acid Functionalized and Crosslinked to Polyvinyl Alcohol/polyamide for Thorium Capturing From Aqueous Solution

“…[47] Pyridine ring vibrations attributable to C=C, C=N, and CÀ N groups are detected at 1602, 1577, 1490, and 1430 cm À 1 . [48] Cross-linking with PDA and the CÀ N group of polyamide was indicated by the reasonably broad tops at 1252 and 1060 cm À 1 . PDA and PVA, which undergo crosslinking, have tops at 1383 and 1341 cm À 1 , which are consistent with free COO-stretching tops.…”