Defence of doctoral thesis: Lukas Marcos Celada – On the Chemical Challenges Towards Green High-Performance Cellulosic Materials

Cellulose stands at a strategic crossroads in the pursuit of a more sustainable materials economy. Whether as a chemical feedstock, a structural component, or a precursor for advanced derivatives and high-performance devices, this pivotal biopolymer continues to drive scientific and technological innovation, even after nearly two centuries of study.

Inspired by this rich scientific legacy, the present thesis aspires to provide new insights into cellulose understanding and valorization. At its core lies a unifying theme: addressing at our level the chemical challenges of cellulose transformation and functionalization, which serves as the red thread throughout this work.

To do so, the first part of this doctoral project explored the synthesis of fully bio-based ionic liquids derived from betaine, specifically designed to exhibit chemical affinity for cellulose. In combination with co-solvents such as dimethyl sulfoxide (DMSO) or acetic acid, one variant was found to facilitate the chemical modification of cellulose, with a range of biorelevant anhydrides.

Building on the methodologies developed using model substrates, these chemical tools were then translated into material design, fostering concepts at the interface between chemical control, tunability, and material engineering. For example, strong and transparent plastic-like materials were obtained via chemically enabled self-densification of delignified wood templates upon simple air-drying. Another example involves the valorization of anhydride-functionalized wood fibers to initiators via radical transfer during classical free radical polymerization under aqueous conditions, resulting in ultra-charged fibers. Beyond the synthetic concept, such materials hold valuable potential for applications in water remediation for example.

Altogether, this thesis aims to bridge as close as possible cellulose green chemistry with material design. By providing efficient and relevant workflows, we hope to contribute and help promote cellulose and cellulosic materials as the pillar of a more sustainable future.