IR-Supported Thermogravimetric Analysis of Water in Hydrogels

Isothermal thermogravimetry in a kinetic mode and time-resolved infrared spectroscopy was used to characterize water and its binding in hydrogels formed by interactions between hyaluronan and micelles of Septonex, an oppositely charged surfactant. Thermogravimetry provided detailed insight into the dehydration kinetics of the gel and thus brought indirect information on the strength of water binding in the hydrogel network. Infrared (IR) spectroscopy complemented the study with a direct analysis of structural changes occurring in the gel during its dehydration. IR spectroscopy thus contributed to understanding the processes which were observed in thermogravimetry, qualitatively, on the molecular level. This study can contribute to a broader application of the combined thermogravimetry–IR approach in the study of hydrogel materials and the development of their applications, especially in bio-related areas where water is among the key players.