The Importance of Interactions at the Molecular Level: A Spectroscopic Study of a New Composite Sorber Material

The functional properties of a new composite material having water vapor getter properties have been investigated by a large arsenal of characterization techniques. The composite system is originated by combining two constituents having very different chemical natures, a magnesium perchlorate (Mg(ClO₄)₂) salt and a polymeric acrylic matrix. In particular, Fourier transform infrared (FT-IR) and Raman spectroscopy have been fundamental to understand the type of interactions between the salt and the matrix in different hydration conditions. It was found that in the anhydrous composite system the dispersed Mg(ClO₄)₂ salt retains its molecular structure, because Mg²⁺ cations are still surrounded by their [ClO₄]^- counter-anions; at the same time, the salt and the polymeric matrix chemically interact each other at the molecular level. These interactions gradually vanish in the presence of water, and disappear in the fully hydrated composite system, where the Mg²⁺ cations are completely solvated by the water molecules.