On the Analysis of Cryogels and Xerogels Using Cellulose Nanofibers and Graphene Oxide

Polymers (Basel). 2023 Sep 20;15(18):3833. doi: 10.3390/polym15183833.

Abstract

Aerogels are highly porous and ultralight three-dimensional materials with great potential for various applications. To obtain highly porous and structurally stable aerogels, a carefully designed synthesis process is required. These materials offer flexibility in manipulating their properties, allowing the incorporation of modifying agents according to specific needs. In this study, compounds were synthesized using graphene oxide (GO) and nanocellulose fibers (NFC) through the hydrothermal reduction methodology. Two drying techniques were employed: lyophilization and oven evaporation, resulting in materials called cryogel and xerogel, respectively. Various parameters that can interfere with the properties of these nanomaterials were evaluated. The results indicated that the cryogel dried by lyophilization provided the best applicability due to its structural flexibility after compressions, whereas the xerogel obtained through the oven evaporation process resulted in a compound with high rigidity and disintegration. Structural characterizations demonstrated the successful development of the precursors and promising characteristics in the synthesized nanomaterials. With its flexibility, approximately 98% porosity, low shrinkage rate, light weight, and electrical conductivity, the developed cryogel showed high potential in various applications, such as pressure sensors, electromagnetic shielding, and other research and development fields.

Keywords: aerogel; cellulose; graphene; hydrothermal reduction; nanomaterials.

Grants and funding

Acknowledgments to the Manna Ecosystem, Araucária Foundation for Scientific and Technological Development of the State of Paraná (F.A.), National Council for Scientific and Technological Development (CNPq)—Brazil, Coordination for the Improvement of Higher Education Personnel—Brazil (CAPES)—Financing Code 001, Softex Campinas Center, Complex of Support Centers for Research (COMCAP-UEM), Multiuser Laboratory of UTFPR Londrina and Apucarana Campuses for the support in this work.