Developments in White Pigment Production Using Biocompatible Cellulose-Based Materials

White pigments are widely used in various everyday products, including paints, food, and cosmetics. The primary choice for achieving white colouration in industries has traditionally been high refractive index inorganic materials, notably titanium dioxide (TiO₂), which recently has raised significant concerns among consumers. Consequently, there is a growing need to explore safer and more biocompatible alternatives. Over the last few years, cellulose-based materials have gained interest in different industrial sectors as well as in fundamental research, basically due to its abundance, biocompatibility, biodegradability, and environmental friendliness. This thesis presents the development of three distinct methods for producing white pigments using cellulose-based nanomaterials. Firstly, an inkjet printing method based on the evaporation-induced phase separation of ethyl cellulose (EC) was developed. The resulting porous films demonstrate enhanced reflectance compared to TiO₂ formulations with equivalent solid content. The inherent biocompatibility of cellulose materials, in conjunction with the simplicity and versatility of inkjet printing, renders this approach highly promising for advanced white colouration production in the printing industry. Secondly, a scalable and straightforward spray-freeze-drying method using natural cellulose nanofibrils (CNFs) was introduced. This approach enables the production of ultra-light and highly porous cellulose aerogel microparticles, thereby opening up the possibility of using natural cellulose material for white pigment particle production. Lastly, a novel method termed as "organic solvent mixing" was developed using cellulose microparticles (CMPs) with optimised scattering dimensions. This proposed method combines the concepts of evaporation-induced phase separation and solvent exchange to address the issue of densification upon water drying. The method successfully yields films with optical properties comparable to those obtained through previously complex techniques. Moreover, this method offers notable advantages, including ease of operation, straightforward implementation, reduced toxicity, and lower cost.