| dc.description.abstract | Derived from the depths of rich, green Canadian forests; the discovery of cellulose nanocrystals (CNCs) has pushed the research and industrial community to find strategic alternatives to replace existing non-renewable building blocks. With the commissioning of world’s largest CNC demonstration plant in Quebec, Canada, the utilization of cellulose nanocrystals is feasible, and has opened a myriad of applications in recent years, such as energy, sensors, water treatment, biometrics, photonics etc.
This dissertation describes the modification of fundamentally inactive CNCs, and converting them into colloidally-active cosmetic systems. In the first approach, the high surface area, and equatorial -OH groups of CNCs were utilized for the nucleation of polyhydroxylated C60 fullerene, as a new antioxidant. The reaction kinetics were quantified and fitted to a pseudo first-order model, and a 2–stage biomolecular reaction mechanism was proposed. This work directly addresses the issue of insolubility that has previously hindered the biological application of the carbon nanocage (C60/C70), and has direct implications for understanding the underlying mechanism of the reaction-kinetics.
At the nanoscale, the surface properties become more dominant than in the bulk-phase due to the relatively higher proportion of atoms at the particle surface. Here, in the second approach a nitrogen-rich porous CNC template enabled the confined growth of semiconductor ZnO, providing a proportionally higher curvature to enhance the active catalytic sites on the metal oxide. The hybrid system was evaluated for in-vitro sun protection factor (SPF) and photocatalytic activity under UV and solar stimulation, and interpreted through the solid-band theory. The reaction kinetics were fit to the Langmuir-Hinshelwood model displaying a 4-fold increase in the photocatalytic activity of the hybrid nanostructure, compared to pure ZnO. Our work suggests that an increase in photocatalysis can be engineered without the introduction of structural defects or tailoring the band gap of ZnO.
To the best of our knowledge, this thesis represents one of the first pioneering studies that reports on the development of optimized personal care systems derived from fCNCs. Our studies showed that the translation of this renewable nanomaterial into scalable cosmetic systems is suggestively viable. | en |
