• cyclopolymerization;
  • polybetaine;
  • polyelectrolyte;
  • polyphosphonobetaine;
  • solution properties;
  • water-soluble polymers


The zwitterionic monomer, ethyl 3-(N,N-diallylammonio)propanephosphonate, was cyclopolymerized in aqueous solutions using t-butylhydroperoxide or ammonium persulfate as initiators to afford a polyphosphonobetaine (PPB). The protonation of P([DOUBLE BOND]O)OEtO and deprotonation of [BOND]NH+ groups in PPB by HCl and NaOH, gave the corresponding cationic polyphosphononic acid (CPP) and anionic polyphosphonate (APP). The presence of two pH-responsive functionalities in APP has led to establish the equilibria: APP ⇌ PPB ⇌ CPP, the position of which very much dictates the viscosity behavior of its aqueous solution. The PPB demonstrated “antipolyelectrolyte” viscosity behavior; however, in contrast to many polycarbo- and polysulfo-betaines, it was found to be soluble in salt-free water as well as in salt-added solutions. Basicity constant (K1) of the amine group in APP, as determined by potentiometric technique, were found to be “apparent,” and as such followed the modified Henderson-Hasselbalch equation. The study demonstrated a correlation between the basicity constants and viscosity values. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010