From a lignin-rich bioresidue to a functional colloid for consumer goods application

Lignin is the second most abundant natural polymer after cellulose and the only large-volume renewable aromatic feedstock found in most terrestrial plants. It is available as bioresidue from several industries, e.g., bioethanol generation, paper and pulp processing, and the food and drink industry. Traditionally, lignin has been burnt for energy generation. However, its unique hydrophobic character, although depending on botanical origin and bioresidue processing method hydrophilic and amphiphilic character have been reported, makes it an interesting material for the design of functional colloidal materials. This is especially interesting in the design of functional colloidal materials for application in consumer goods, such as foods and personal care products, where chemically modified ingredients tend to be consumer adverse. While lignin nanomaterials are not per-se novel, there is little understanding how to design these for application in specific products to assume the required functionality. In particular intriguing is the observation that lignin nanoparticles are mostly described for the stabilisation of oil-in-water emulsions despite the predominantly hydrophobic character of lignin. In non-consumer goods application, these materials have been applied to reinforce structures.

The overall aim of this PhD project is to further our understanding of the functional properties of lignin colloidal materials to develop design rules for their application as sustainable ingredient in consumer goods. The research focus will be subject to discussion between researcher and student. It could be the stabilisation of interfaces, in food or personal care formulations, or functionality as inert filler particle in fat continuous matrices. Research methods will be similar including extraction, chemical fingerprinting by spectroscopy, colloid processing, interfacial tension and rheology, contact angle, rheology,