Finding alternatives to fluorinated compounds (PFAS) involves very diverse application areas. Among them, the treatment of technical textiles to make them water- and oil-repellent is a major challenge for manufacturing protective clothing against both aqueous and oily contaminants. Our laboratory is developing such alternatives by covalently grafting molecules onto fibers selected from those already used for technical textiles. The thesis will focus on experimental work with two components. The first component will consist of improving and qualifying, at a semi-industrial level, the water- and oil-repellent properties already obtained and qualified according to current standards (water and oil droplet sliding, slow impregnation of oil droplets) using our nanometric chemical coatings. The second component will be dedicated to optimizing the weave structure, in conjunction with the chemical treatment, to determine the optimal weave based on the desired properties. The work will be carried out in close contact with a technical textile manufacturer and with ENSAIT in Roubaix.