Complexation of polyacrylamide and poly(<i>N</i>‐isopropylacrylamide) with poly(acrylic acid). The temperature effect

Abstract

Abstract We present potentiometric and viscometric results on the interpolymer complexation between polyacrylamide (PAAM) and poly( N ‐isopropylacrylamide) (PNIPAAM) with poly(acrylic acid) (PAA) in dilute aqueous solution. A potentiometric procedure for the determination of the complex stoichiometry in monomeric units has been proposed. The temperature dependence of the strength of the complex formed has been investigated. From the results obtained it has been concluded that hydrogen bonding is the main factor stabilizing the PAAM/PAA complex, strengthened by decreasing the temperature while the much stronger PNIPAAM/PAA complex, strengthened by increasing the temperature, is stabilized by hydrophobic interaction.