Gellan-Based Hydrogels and Microgels for culturage heritage: a rheological perspective

TL;DR

This study thoroughly characterizes the rheological properties of gellan-based hydrogels and microgels, focusing on their viscoelastic behavior and gelation process, to optimize their use in paper restoration.

Contribution

It provides detailed insights into the rheological behavior and gelation mechanisms of gellan hydrogels and microgels, aiding in their application for cultural heritage conservation.

Findings

Gellan hydrogels exhibit double yielding behavior under cleaning conditions.

Temperature, gellan concentration, and cations significantly influence gelation.

Prepared microgels show high reproducibility and controlled properties.

Abstract

Gellan gum has gained significant attention due to its versatility in multiple applications in the form of hydrogels and microgels. A thorough understanding of the rheological behaviour of these systems is crucial both for fundamental research and to optimize the manufacturing needs. To this aim, here we extensively characterize the rheological behaviour of gellan based hydrogels and microgels recently used for efficient paper cleaning for restoration interventions. In particular, we study their viscoelastic properties, also during hydrogel and microgel formation, assessing the role of temperature, gellan concentration, and, importantly, the presence of different cations, which plays a crucial role in the gelation process. We find the interesting result that, in the conditions where they are efficient for cleaning, gellan hydrogels exhibit a double yielding behavior. In addition, we provide a detailed description of gellan microgels preparation, ensuring high control and reproducibility of the samples. Altogether our study sheds light on the mechanical stability, network structure, and overall functionality of the gellan-based gels, providing valuable insights into optimizing conditions for desired applications in paper cleaning.