Fe(II) Spin Crossover/Polymer Hybrid Materials: Investigation of the SCO Behavior via Temperature-Dependent Raman Spectroscopy, Physicochemical Characterization and Migration Release Study

Abstract

Polymeric composites constitute an appealing class of materials with applications in various fields. Spin crossover (SCO) coordination complexes are switchable materials with potential use in data storage and sensors. Their incorporation into polymers can be considered an effective method for their wider practical application. In this study, Fe(II) SCO/polylactic acid hybrid polymeric composites have been prepared by film casting. The mononuclear coordination complex [Fe{N(CN)2}2(abpt)2] was incorporated into polylactic acid. The morphological, structural and thermoanalytical characterization of the composite films were performed via scanning electron microscopy (SEM), attenuated total reflectance (ATR/FTIR), Raman spectroscopy and differential scanning calorimetry (DSC). In addition, the migration release study (MRS) of the SCO compound from the polymeric matrix into the food simulant 50% v/v water/ethanol solution was also examined via UV/Vis absorption. Of particular interest was the investigation of the SCO behavior of the coordination complex after its incorporation into the polymer matrix; it was accomplished by temperature-dependent micro-Raman spectroscopy. The described attempt could be considered a preparatory step toward the development of SCO-based temperature sensors integrated into food packaging materials.

Tuning the Spin-Crossover Behaviour in Fe(II) Polymeric Composites for Food Packaging Applications

“…The incorporation of SCO complexes into polymers could be considered important, in terms of technological applications which aim at highlighting the physical characteristics of the material [10,[12][13][14]. In this context, different types of integration processes have been examined, including spray coating, film casting, electrospinning, and 3D printing or even through the chemical reaction of the SCO compound with the polymer [14][15][16][17]. Film casting could be considered one of the preferable preparation methods ensuring the stability of the complex after its incorporation into the polymer.…”