Polyampholyte terpolymers of amphoteric, amino acid‐based monomers with acrylamide and (3‐acrylamidopropyl)trimethyl ammonium chloride

作者：Ryan G. Ezell, Irene E. Gorman, Bradley S. Lokitz, Neil D. Treat, Shawn D. McConaughy, Charles L. McCormick · 发表于：Journal of Polymer Science Part A Polymer Chemistry · 年份：2006 · DOI：10.1002/pola.21543 · 被引用次数：22 · 研究领域：Electrostatics and Colloid Interactions、Surfactants and Colloidal Systems、Advanced Polymer Synthesis and Characterization

Abstract Low‐charge‐density amphoteric copolymers and terpolymers composed of acrylamide, (3‐acrylamidopropyl)trimethyl ammonium chloride, and the amino acid derived monomers ( e.g. , N ‐acryloyl valine, N ‐acryloyl alanine, and N ‐acryloyl aspartate) were prepared via free‐radical polymerization in aqueous media to yield terpolymers with random charge distributions and homogeneous compositions. Sodium formate (NaOOCH) was employed as a chain transfer agent during the polymerization to suppress gel effects and broadening of the molecular weight distribution. Terpolymer compositions were determined by 13 C and 1 H NMR spectroscopy. Terpolymer molecular weights and polydispersity indices were obtained via size exclusion chromatography/multi‐angle laser light scattering, and hydrodynamic diameter values were obtained via dynamic light scattering. The solution properties of low‐charge‐density amphoteric copolymers and terpolymers have been studied as a function of solution pH, ionic strength, and polymer concentration. The low‐charge‐density terpolymers display excellent solubility in deionized (DI) water with no phase separation. The charge‐balanced terpolymers exhibit antipolyelectrolyte behavior at pH values ≥(6.5 ± 0.2). As solution pH is decreased, these charge‐balanced terpolymers become increasingly cationic because of the protonation of the anionic repeat units. Charge‐imbalanced terpolymers generally demonstrate polyelectrolyte behavior, although the effects of intramole...