Atom transfer radical polymerization as a tool for making poly(N-acryloylglycinamide) with molar mass independent UCST-type transitions in water and electrolytes

Abstract

Atom transfer radical polymerization (ATRP) of N-acryloylglycinamide has been used as a tool to make poly(NAGA) showing UCST-type phase transitions in water and electrolytes independent of molar mass and end-groups. We hypothesized that similarity in the structure of polymer chain ends with the repeat unit of poly(NAGA) could help in eliminating the effect of molar mass dependence of the cloud point especially in the low molar mass region. The monomer-like end-groups were introduced by choosing an appropriate initiator for ATRP like chloropropionamide (CPA). The catalyst system CuCl/CuCl₂ and tris[2-(dimethylamino)ethyl]-amine (Me₆TREN) as a ligand provided controlled polymerization of NAGA in DMSO at 45 °C with UCST-type transitions retained in water and electrolytes without being influenced by chain ends/molar mass and high concentration of salts like NaCl and Na₂SO₄.