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A series of polyurethanes were synthesized from poly(isopropyl lactate)diol, poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) triblock copolymer, and different aliphatic diisocyanates. The chemical structure and molecular characteristics were investigated by 1H NMR, FT-IR, and GPC analysis. The effect of the isocyanate moiety on the polymer properties was studied. The wetting properties were evaluated from the contact angle determination. The obtained water-soluble polyurethanes present very low critical micelle concentration as determined by surface tension measurements. Aqueous solutions of these polyurethanes underwent a sol–gel–sol transition in a certain range of temperature, as a function of their chemical composition. The gelation for aqueous polyurethane solutions has been also realized under isothermal condition, and the viscoelastic properties of the hydrogels at 37 °C were investigated. The chemical structure of the diisocyanates influences the gelation process as well as the properties of the polyurethane hydrogels. These polyurethane properties might aid in devising new theoretical and practical approaches in many areas, such as pharmacology and materials fabrication.

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Polyether urethane (PU)-based magnetic composite materials, containing different types and concentrations of iron oxide nanostructures (Fe2O3 and Fe3O4), were prepared and investigated as a novel composite platform that could be explored in different applications, especially for the improvement of the image quality of MRI investigations. Firstly, the PU structure was synthetized by means of a polyaddition reaction and then hematite (Fe2O3) and magnetite (Fe3O4) nanoparticles were added to the PU matrices to prepare magnetic nanocomposites. The type and amount of iron oxide nanoparticles influenced its structural, morphological, mechanical, dielectric, and magnetic properties. Thus, the morphology and wettability of the PU nanocomposites surfaces presented different behaviours depending on the amount of the iron oxide nanoparticles embedded in the matrices. Mechanical, dielectric, and magnetic properties were enhanced in the composites’ samples when compared with pristine PU matrix. In addition, the investigation of in vitro cytocompatibility of prepared PU nanocomposites showed that these samples are good candidates for biomedical applications, with cell viability levels in the range of 80–90%. Considering all the investigations, we can conclude that the addition of magnetic particles introduced additional properties to the composite, which could significantly expand the functionality of the materials developed in this work.