Interpolymer complexes of a graft copolymer with polyelectrolytes and equivalent blends of binary homopolymer complexes: A comparative study of their stability and thermodynamic parameters

Abstract

Interpolymer complexes of acrylamidehinyl alcohol graft copolymers (AAmNA) were prepared with two typical polyelectrolytes, e. g. poly(methacry1ic acid) (PMA) and poly(ethy1eneimine) (PEI). The equivalent blends of the same composition as the graft copolymer complexes were also prepared by mixing stoichiometric portions of binary homopolymer complexes. The stability constant (K), degree of linkage (8) and related thermodynamic parameters (e. g. standard free energy change AGO, standard enthalpy change AHo and standard entropy change ASo) were determined for each system by using Osada's method. The comparative study between graft copolymer complexes and equivalent blends indicated a considerable difference in these parameters. An interpretation of this discrepancy was sought in terms of copolymer effect, neighbouring group influence, and the nature of secondary binding forces upon interpolymer complexation.

Complexation Phenomena in pH-Responsive Copolymer Networks with Pendent Saccharides

“…[2][3][4][5][6][7][8][9][10][11][12] Typically, polymer networks containing poly(methacrylic acid) (PMAA) or poly(acrylic acid) (PAA) can form polyelectrolytic or hydrogen-bonded complexes that are strongly dependent on the environmental pH and ionic strength. [13][14][15][16][17][18][19] For example, Kono et al 14 made use of the polyelectrolyte complexation between PAA and polyethyleneimine (PEI) to form pH-sensitive capsules that could release their contents in response to pH changes. Lowman et al [15][16][17] studied the complexation of poly(methacrylic acid-g-ethylene glycol) (P(MAA-g-EG)) networks due to hydrogen bonding by investigating swelling/deswelling process and stress-strain behavior depending on the surrounding pH change.…”