oil-in-water emulsions are widely used in various industrial applications such as food, pharmaceuticals, and cosmetics. an oil-in-water emulsion is a colloidal system in which oil droplets are dispersed in water with the help of emulsifiers. the emulsifiers can stabilize the oil droplets in the water phase, preventing them from coalescing and being separated from the water, resulting in a stable mixture that can be used in various industrial processes. lignin macromolecules, derived from renewable biomass resources, have gained extensive interest during the past decade as a sustainable substitute for oil-based synthetic materials. one of the goals of this dissertation was to formulate and develop a lignin-based emulsifier that is renewable, biodegradable, and non-toxic from the molecular level to the macroscopic level. to obtain the desired physicochemical properties, chemical modifications were conducted. we utilized solventfree reactions to synthesize sulfo-alkylated lignin-based emulsifiers in a facile green process. oilin-water emulsions were formulated in the presence of emulsifiers, and a vertical scan analyzer was used to monitor their stability to show their potential for stabilizing emulsions. [...]