Description du sujet de thèse

Context
This PhD is part of the ANR FLIGHT project, which aims to replace petroleum-based plastics with bio-based alternatives by exploiting lignin, an abundant, renewable, and underutilized by-product of the paper and wood industries. While lignin has unique chemical properties, its direct use in high-performance applications remains limited. FLIGHT addresses this gap by developing eco-friendly processes to transform lignin into composites, membranes, and insulation panels, fully characterized and benchmarked against fossil-based materials.
A critical step in this value chain is the production of lignin fibers and nanofibers, which will serve as the building blocks for high value-added materials.
Objectives of the PhD
The PhD candidate will focus on designing and optimizing green spinning processes for lignin-based fibers, relying exclusively on enzymes and water, avoiding toxic organic solvents. The work will consist of:
• Enhancing lignin solubility through enzymatic treatment with Bilirubin Oxidase (BOD), a novel approach that improves processability while maintaining polymer integrity.
• Developing and optimizing dry-spinning, wet-spinning, and electrospinning routes for the production of continuous microfibers (10–100 µm) and nanofiber mats (100–1000 nm).
• Conducting in-depth rheological studies (shear and extensional viscosity, phase diagrams) to understand and control fiber formation mechanisms.
• Characterizing the structural, mechanical, and surface properties of the fibers to evaluate their suitability for advanced applications.
Role within the FLIGHT project
The fibers produced during the PhD will be transferred to project partners for further processing and demonstration. Specifically:
• Composite demonstrators will be manufactured by embedding lignin fibers into bio-based matrices, replacing glass fibers with lighter, more sustainable reinforcements.
• Filtration membranes will be produced using lignin nanofiber mats obtained by electrospinning, with potential applications in pollution control and water treatment.
• Insulation panels will be explored using powder-based or fiber-mat approaches, offering thermal and acoustic performance with a reduced environmental footprint.
Expected outcomes
The thesis will establish reproducible, scalable, and environmentally friendly methods for lignin fiber production, providing essential feedstock for the FLIGHT consortium to design sustainable bio-based materials. The work will contribute both fundamental insights into lignin processability and practical outputs in the form of fiber prototypes for partner-led applications, paving the way to industrial uptake and potential patents.

Contexte de travail

The work will be carried out within the Carbon Nanotubes and Graphene and Biotech teams of the CRPP, under the supervision of Philippe Poulin and Nicolas Mano. The CRPP is a physical chemistry laboratory, a joint unit of CNRS – University of Bordeaux. It conducts research in various fields, ranging from soft matter to biology to synthetic chemistry. The laboratory benefits from numerous academic and industrial partnerships in France and worldwide. Its openness, recognition, and state-of-the-art equipment make it an ideal place to begin a career in scientific research.
The laboratory has all the necessary equipment for the thesis: from bioreactors for lignin solubilization to spinning and electrospinning devices, as well as structural characterization tools (microscopy, X-ray, spectroscopy), and mechanical and rheological equipment.

Le poste se situe dans un secteur relevant de la protection du potentiel scientifique et technique (PPST), et nécessite donc, conformément à la réglementation, que votre arrivée soit autorisée par l'autorité compétente du MESR.

Contraintes et risques

No particular risks.