Competitive hydrogen-bonding interactions in modified polymer membranes: a density functional theory investigation.

The subject of this work is the density functional theory (DFT) investigation of competitive hydrogen-bonding interactions that occur in modified block poly(ether/amide) (PEBAX) membranes. Previously, an evaluation of hydrogen-bonding interactions occurring between N-ethyl-o,p-toluensulfonamide (KET) modifiers was performed to establish the role of these interactions in affinity processes when the modifier is dissolved in PEBAX matrixes. However, some issues related to polymer-polymer (host-host) and modifier-polymer (host-guest) interactions were not analyzed from a theoretical point of view in the previous analysis. Here, a comparative computational analysis of these intermolecular interactions is discussed. New insights into the role of hydrogen bonding in domino processes are provided. Calculations in solvent and in vacuum have been done, yielding indications about the change in the availability of the polar groups of the polymer, which is considered to be partially responsible for the enhanced hydrophilicity of the membranes. This study can open the way to the construction of new predictive quantum modeling approaches for designing improved modifiers, enabling the optimization of polymer membrane performance.