Qualitative Investigation on some H-bonded Interpolymer Complexes by Determination of Thermodynamic Parameters

Abstract

Qualitative analysis for stability of some hydrogen bonded interpolymer complexes of poly (acrylic acid) with non ionic polymers such as poly (methacryl amide) (PMAm), poly (vinyl pyrrolidon) (PVP), poly (ethylene oxide) (PEO) and poly (ethylene glycol) (PEG), has been done by determining the stability constant (K) and thermodynamic parameters (e.g. ΔH<sup>0</sup> and ΔS<sup>0</sup>) of these complexes at several temperatures. The comparative studies indicate considerable difference in the values of these parameters. They can be explained on the basis of influence of other interacting forces such as hydrophobic and ion dipole interactions during interpolymer complex formation. It has been found that the stability of H-bonding interpolymer complex is greatly enhanced by these two factors.

Preparation of a Bioadhesive Poly(Acrylic Acid)/Polyvinylpyrrolidone Complex Gel and Its Clinical Effect on Dental Hemostasis

“…However, thermodynamic analysis of their complex formation behavior revealed that the entropy change was positive for the complexing process. This suggests that hydrophobic interaction between the polymers is another one of the main driving forces for the formation of water-insoluble complexes [ 23 ]. Hydrophobic bonding is a relatively weak intermolecular force, and large hydrophobic groups are required to provide a strong binding force.…”

“…The carboxylic acid groups in the PAA side chains play an important role in adhesion [ 14 , 28 ]. In the PAA/PVP complex, where both polymer chains are aligned in a zipper-like structure [ 22 ], most carboxyl groups are consumed by hydrogen bonding with the pyrrolidonyl groups of the PVP molecules [ 23 ]. In contrast, in the complex obtained by mixing PAA and PVP in the presence of HA, the parallel lining of PAA and PVP was inhibited, and not a little carboxyl groups remained in the nonbinding state.…”

“…However, simple mixing of aqueous PAA and PVP solutions resulted in a non-adhesive precipitate, which was neither soluble nor swollen in water. The formation of the hydrophobic complex is caused by hydrophobic interactions between the main chains of both polymers aligned the same as a zipper [ 22 , 23 ]. We expected that a water-absorbing complex could be obtained if the parallel polymer main chains were disturbed.…”

Poly(acrylic acid) interpolymer complexes

“…Hydrogen bonding is one of the most important factors to consider in the self-assembly of both natural and synthetic macromolecules 1 . However, even a comparatively simple polymer such as poly(acrylic acid) (PAA), a weak polyelectrolyte, experiences a range of other interacting forces (such as hydrophobic and ion-dipole interactions), which affect complex stability and can drive phase transitions [2][3][4] .…”

“…Complexation with a variety of water soluble polymers were studied. Many of these systems have previously been studied, and besides pH IPC binding can vary depending on bothtemperature, concentration, molar mass and ionic strength [2][3][4][5][6][7][8] . For this study we have measured dilute solutions (0.1-0.5 mg ml -1 ), at low ionic strength at room temperature (18-22 ˚C) to ensure results are comparable.…”