Macromolecules, Vol.41, No.21, 8198-8203, 2008
Shapes of Polyelectrolyte Titration Curves. 2. The Deviant Behavior of Labile Polyelectrolytes
Hydroxypropyl guar (HPG), a nonionic water soluble polymer, becomes an anionic polyelectrolyte in the presence of borate or boronate ions which bind to HPG. However, the charge groups on the HPG-borate are labile which complicates the interpretation of polyelectrolyte titration behavior. Specifically, polyelectrolyte complex formation between HPG-borate and cationic poly(diallyldimethyl ammonium chloride), PDADMAC, stimulates further borate binding to HPG. We propose that labile polyelectrolytes such as HPG-borate are new class of polylelectrolytes that fall outside conventional "strong" or "weak" polyelectrolyte behavior.