Exploring the Hofmeister effect on guar gum dispersions: a machine learning and data fusion approach combining infrared spectroscopy and thermal analysis

Specific ion effects, as described by the Hofmeister series, play a crucial role in modulating the physicochemical behavior of macromolecular systems. In polysaccharide aqueous dispersions these effects are closely related to modifications of the polymer–water hydrogen-bonding network, although their interpretation remains challenging due to the complex interplay between ions, water, and macromolecular structure. In this study, we investigate the effect of kosmotropic and chaotropic cosolutes on guar gum aqueous dispersions by integrating Attenuated Total Reflectance–Fourier Transform Infrared (ATR-FTIR) spectroscopy and thermogravimetric analysis (TGA) using multivariate analysis and data fusion strategies. Distinct ion-specific modifications were observed in both the hydroxyl stretching region and the dehydration behavior of the galactomannan system. Principal Component Analysis (PCA) applied to the individual datasets revealed distinct ion-specific trends while a mid-level data fusion approach based on the Common Dimensions (ComDim) algorithm further improved sample clustering and visualization. Loading and salience analyses identified the main spectral and thermal features associated with ion-dependent perturbations of the guar gum–water network. The proposed methodology highlights the potential of integrated spectroscopic, thermal, and chemometric approaches for investigating hydration-mediated phenomena in polysaccharide systems and, more broadly, in complex macromolecular materials.