The viscoelastic behavior of the precursor hydrogels can modify aerogel properties

The effect of the rheological properties of alginate crosslinked hydrogels on their respective aerogels (dried with supercritical carbon dioxide) was investigated in this work. It was observed that aerogels with larger specific surface area (from 115 to 320 m2·g−1) were obtained from precursor hydrogels with higher storage modulus (from 1200 to 22,000 Pa). Likewise, according to the thermogravimetric results, more stable aerogels were obtained from hydrogels with a stronger solid-like behavior. These phenomena were explained considering simultaneously the higher number of formed junctions due to the crosslinking reaction and the higher zero-rate viscosity of the initial solutions. However, the rheological properties did not play an important effect concerning the type of aerogel morphology (nanofibrous) or the isotherm adsorption (type IV). Moreover, this work also showed that hydrogels with a predominant elastic nature provides a lag time in the drug release, that was numerically studied considering for the first time the imbibition phenomenon in a compartmental model.