Cellulose is a crucial constituent of the structure of all living plants. It possesses a complex structure including chirality. Its fascinating structural features combined with its impressive properties in terms of specific strength and stiffness has triggered the engineering of cellulose-based materials with tailored mechanical and optical properties. The developments of pixelated STEM detectors as well as hybrid pixel detectors have enabled the collection of scanning electron diffraction (SED) data. This type of systems allow for very rapid acquisition of 2D SED maps using a very low beam dose (~6 e-/Å2). This is crucial for obtaining data from a beam sensitive material such as cellulose. A high-level optical system allows for the formation of a pencil beam with the size of 1-5 nm while keeping a small convergence angle. The resulting SED data can be analysed in various ways to produce maps revealing the crystalline microstructure of cellulose nanofibers (CNFs) and cellulose nanocrystals (CNCs). SED data can be used to study the local crystallographic ordering within CNFs and how it is evolving along the fibers. CNFs has been extensively studied by AFM and electron microscopy imaging and twisting domains have been investigated based on morphological studies. SED data now makes it possible to study the evolution of the crystallographic structure through the twisting sections of the CNFs. One advantage of SED data over conventional electron diffraction is that the small probe sized enables the study of the local microstructure not just along the cellulose nanofibers but also in its transverse direction. This enables the comparison of local ordering of polysaccharide chains within CNFs extracted from tunicate and CNCs of bacterial origin revealing the difference in local crystalline structure.

Scanning electron diffraction as a tool to study the local crystallinity of cellulose

Macromolecular Chemistry: The Second Century

[Author Benefits](https://scimeetings.acs.org/?utm_source=pubs_content_marketing&utm_medium=website&utm_campaign=0320_MCF_NPI_Launch_Spring_Homepage&ref=pubs_content_marketing)

[How to use SciMeetings](https://storage.googleapis.com/dl.morressier.com/acs/SciMeetings-ACSSpring2020-HowToGuide_M3020-Final.pdf)

[Frequently Asked Questions](https://storage.googleapis.com/dl.morressier.com/acs/SciMtng_ACSNMSp2020_FAQ_M3120_Final.pdf)

ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.