Cellulose Nanofoams: 3D Printing and Characterization

Abstract

In recent years, the advancement in cellulosic nanofoams has been considerable. Yet, their customization potential for diverse application requirements has been constrained by reproducibility challenges. Our research, therefore, focused on two primary objectives: enhancing the thermal regulation capabilities and mechanical properties of cellulose nanofibrils (CNF) nanofoams, and developing a reproducible methodology for printing customized three-dimensional (3D) structures using direct-ink-write (DIW) technology and molding.

We developed composite nanofoams using TEMPO-modified cellulose nanofiber (TCNF). The resultant composite nanofoams showcased remarkable properties such as ultra-low thermal conductivity, low density, outstanding flexibility, and infrared shielding capabilities.

In a bid to create robust and environmentally friendly nanofoams, we employed a crosslinking process with CaCl2. The crosslinked nanofoams were extraordinarily lightweight yet boasted superior mechanical properties, significantly amplified by the crosslinker. Remarkably, these freeze-dried T-CNF/CaCl2 nanofoams maintained their form and demonstrated admirable flexibility, even when subjected to weight exceeding thousands of times their own. Furthermore, transient characterization confirmed their excellent thermal insulation capabilities.

In conclusion, our research has pioneered the fabrication of sustainable, high-stability cellulose nanofoams. We have significantly enhanced the thermal management capabilities and mechanical performance of these nanofoams, marking a remarkable advancement in the field. The demonstrated sustainability, biocompatibility, ultra-light weight, high porosity, and deformability of the resultant nanofoams suggest considerable potential for diverse applications, including thermal insulation, shock and vibration damping, as well as tissue engineering.