Synthesis and characterization of novel thermo- and salt-sensitive amphoteric terpolymers based on acrylamide derivatives

A novel linear amphoteric terpolymers based on neutral monomer — N-isopropylacrylamide (NIPAM), ani- onic 2-acrylamido-2-methyl-1-propanesulfonic acid sodium salt (AMPS), and cationic mono- mer (3-acrylamidopropyl) trimethylammonium chloride (APTAC) were synthesized by free-radical polymerization in aqueous solution characterized methods of 1H NMR FTIR spectroscopy, TGA, GPC, Dynamic light scattering (DLS) zeta-potential. The thermal sensitivity ternary polymers various compositions, particularly, [NIPAM]:[AMPS]:[APTAC] = 90:2.5:7.5; 90:5:5; 90:7.5:2.5 mol.% studied aqueous-salt solutions the temperature range from 25 to 60 C at NaCl ionic strength  interval 10–3 1M. It was found that due hydrophobic/hydrophilic balance, dependent conformational phase change macromolecular chains becomes sensitive addition allows fine-tuning transition. In solutions, average hydrodynamic size is varied 8 300 nm exhibiting bimodal distribution room temperature. number (Mn) weight (Mw) molecular weights, polydispersity index (PDI), zeta-potentials solu- tions determined