Synthesis of ionic polyurethanes with pyrene rings: Spectral properties and fluorescence quenching study

Abstract

Hydrophilic ionic polyurethanes with 4‐chloromethylphenylcarbamoyl‐1‐oxymethylpyrene located on the quaternary ammonium structure from a polymer based on poly(ethylene glycol), isophorone diisocyanate, and N‐methyldiethanolamine were prepared by a quaternization reaction, in which the amount of pyrene covalently attached to the polymeric backbone ranged from 1.14 to 19.82 mmol of fluorophore/100 g of polymer. It was interesting to compare the photoluminescence of the pyrene polyurethane carrying a few mole percent of pyrene moieties with that of a third polymer resulting from its subsequent quaternization with benzyl chloride up to a concentration of ionic groups as in the latter (quaternization degree = 14.15%). The process of excimer formation between the pyrene molecules attached to the ionic polyurethane was investigated in tetrahydrofuran (THF), dimethylformamide, film, and THF/H2O to illustrate the expected differences in the polymer behavior compared with that of the starting pyrene derivative. The formation of aggregates or core–shell micelles was sustained by the fluorescence data, which indicated the existence of pyrene units in the ground state of the molecule, giving rise thus to an explanation for the high excimer‐to‐monomer intensity ratio. The fluorescence decay of pyrene polyurethanes in the presence of various concentrations of nitrobenzene used as a quencher was analyzed too when the fluorescence quenching in the polymer solution normally followed Stern–Volmer kinetics. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3945–3956, 2005

Effect of microstructural arrangement of MDI‐based polyurethanes on their photoproperties

“…For example, chromophores have been introduced as a pendent group during the quaternization of polyurethanes to study their film and solution properties. In addition, nitrobenzene has been used as a quencher in polyurethane systems that contain pyrene as a pendent group bound to the backbone of the polymer . The synthesis and characterization of polyurethane cationomers with anthracene chromophores attached to quaternary ammonium units have also been discussed in the literature .…”

Synthesis and properties of polyurethane cationomers with urethane-cholesteryl and dodecylmethylammonium moieties

“…Also, we are interested in ionic polyurethanes containing poly(ethylene glycol) segments into their structure, since it has been frequently used as co-monomer in preparing biodegradable polymers due to its biocompatibility and biodegradability [29]. In addition, such amphiphilic block co-polymers can self-assemble into organized structures in selective solvents [30].…”

Synthesis and characterization of polyurethane cationomer/MMT hybrid composite

“…In view of our experience related to polyurethane ionomers designed for various applications,32–35 we decided to investigate the synthesis and characterization of novel polyurethane cationomers with ionic sequences incorporated via the quaternization of tertiary aliphatic amines together with the corresponding hybrid composites obtained by employing different quantities of organically modified MMT (OM‐MMT), accompanied by an evaluation of their mechanical properties.…”