Influence of alkali metal counterions on the charging behavior of poly(acrylic acid)

✍ Scribed by Amin Sadeghpour; Andrea Vaccaro; Samuel Rentsch; Michal Borkovec

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 486 KB
• Volume: 50
• Category: Article
• ISSN: 0032-3861
• DOI: 10.1016/j.polymer.2009.06.032

✦ Synopsis

a b s t r a c t Charging of poly(acrylic acid) (PAA) in the presence of different alkali metal counterions was studied by precision potentiometric titration. The charging behavior can be described with a novel cylinder Stern model quantitatively. This model is based on the Poisson-Boltzmann equation in the cylinder geometry and a constant Stern capacitance. One finds an increasing cylinder radius with increasing mass of the alkali metal ion and a correspondingly decreasing Stern capacitance. The intrinsic ionization constants for the uncharged polymer are found to decrease with ionic strength, similarly to weak acids of low molecular mass.