Influence of triphenylphosphonium pendant groups on the rheological and morphological properties of new quaternized polysulfone

Abstract

A new quaternized polysulfone with triphenylphosphonium pendant groups was synthesized by reacting chloromethylated polysulfone with triphenylphosphine. The molecular restructurations, generated by hydrogen bonding, electrostatic interactions, and association phenomena in ternary quaternized polysulfone/N,N-dimethylformamide (solvent)/water (nonsolvent) systems, were evaluated by rheological investigations. The polyelectrolyte effect, induced by enhanced dissociation of the ionizable groups and by mixed solvents' quality, modify the rheological functions, that is, dynamic viscosity, elastic shear modulus, and viscous shear modulus, as well as the thermodynamic parameters obtained from the rheological properties, such as apparent activation energy. These results were correlated with the morphological properties of the films obtained from solutions in solvent/nonsolvent mixtures and compared with other quaternized polysulfones, having different hydrophobic characteristics.

Establishing proper scanning conditions in atomic force microscopy on polyimide and polyurethane samples and their effect on 3D surface texture parameters

“…Atomic force microscopy (AFM; Binnig et al ., ) is a powerful characterization tool for a broad range of polymer materials, such as bulk polymers (Pfau et al ., ; Ioan et al .,; Buruiana et al .,), block copolymers (McLean and Sauer ), polymer blends (Cosutchi et al ., ; Albu et al ., ; Filimon et al ., ; Onofrei et al ., ; Nica et al ., ), polymer composites (Vanlandingham et al ., ; Alexandru et al ., ) and thin polymer films (Passeri et al ., ; Domke and Radmacher ), capable of revealing surface structures with superior spatial resolution. Usually, AFM measurements can generate unwanted artifacts on the morphological images (Kühle et al ., ), some of them induced by tip, scanner, vibrations, feedback circuit, or image‐processing software (Braga and Ricci, ) and others induced by nonlinear relationship between cantilever deflection and laser spot movement or nonlinear detector response (Thormann et al ., ).…”