Assembling Native Elementary Cellulose Nanofibrils via a Reversible and Regioselective Surface Functionalization

Selective surface modification of biobased fibers affords effective individualization and functionalization into nanomaterials, as exemplified by the TEMPO-mediated oxidation. However, such a route leads to changes of the native surface chemistry, affecting interparticle interactions and limiting the development of potential supermaterials. Here we introduce a methodology to extract elementary cellulose fibrils by treatment of biomass with N-succinylimidazole, achieving regioselective surface modification of C6-OH, which can be reverted using mild post-treatments. No polymer degradation, cross-linking, nor changes in crystallinity occur under the mild processing conditions, yielding cellulose nanofibrils bearing carboxyl moieties, which can be removed by saponification. The latter offers a significant opportunity in the reconstitution of the chemical and structural interfaces associated with the native states. Consequently, 3D structuring of native elementary cellulose nanofibrils is made possible with the same supramolecular features as the biosynthesized fibers, which is required to unlock the full potential of cellulose as a sustainable building block.

Automated summary

Selective surface modification of biobased fibers allows for individualization and functionalization into nanomaterials using TEMPO-mediated oxidation, but can lead to changes in native surface chemistry. A methodology is introduced to extract cellulose fibrils with regioselective surface modification, which can be reverted with mild post-treatment, without polymer degradation or changes in crystallinity. This offers significant potential in reconstituting the chemical and structural interfaces of native states for sustainable building blocks.