The nanoscale ordering of cellulose in a hierarchically structured hybrid material revealed using scanning electron diffraction

Cellulose, being a renewable and abundant biopolymer, has garnered significant attention for its unique properties and potential applications in hybrid materials. Understanding the hierarchical arrangement of cellulose nanofibers is crucial for developing cellulose-based materials with enhanced mechanical properties. In this study, we present the use of Scanning Electron Diffraction (SED) to map the nanoscale orientation of cellulose fibers in a bio-composite material with a preserved wood cell structure. The SED data provides insights into the ordering of cellulose and enables quantitative analysis of the fiber orientation within the composite with a resolution of ~15 nm. We observed a highly organized arrangement of cellulose fibers within the secondary cell wall, with a gradient of orientations towards the outer part of the wall. The in-plane fiber rotation was quantified, revealing a uniform orientation close to the middle lamella. Transversely sectioned material exhibited similar trends, suggesting a layered cell wall structure. Based on the SED data, we constructed a 3D model depicting the complex helical alignment of fibers throughout the cell wall. This study demonstrates the unique opportunities SED provides for characterizing the nanoscale hierarchical arrangement of cellulose nanofibers, empowering further research on a range of hybrid materials.