Synthesis and Characterization of Novel Nanomaterials Based on Nanocrystalline Cellulose

Modern technologies have contributed to develop our society in all different fields. The trend in current research pulls towards the development of sustainable materials, to address concerns about environmental impact. Cellulose, one of the most ubiquitous and abundant bio-resources originating from higher plants, tunicate, bateria and algae, has become attractive from the viewpoint of sustainable development. Nanocrystalline cellulose (NCC), a rod-shaped nanoscale material with exceptional strength and physicochemical properties, can be prepared from this inexpensive renewable biomass. Besides its potential use as a reinforcing agent for industrial biocomposites, pristine NCC exhibits low toxicity and poses no serious environmental concerns, providing impetus for its use in bioapplications. The chemistry of NCC is dominated by the abundance of hydroxyl groups on its surface, which can be readily converted into other functional groups or used directly to bind compounds in a non-covalent way. Both approaches are exploited in this Thesis to obtain new NCC based hybrid nanomaterials with applications ranging from energy to catalysis to drug delivery. In all cases, the synthesis and full characterization are presented. Concerning non-covalent chemistry, NCC was proposed as exfoliating agent of 2D materials in water to obtain sustainable, cost-effective energy storage devices. Regarding covalent functionalization, two different pathways were applied to modify NCC surface. The first one consisted on its oxidation to introduce carboxylic groups followed by the attachment of amino-terminated fullerene derivatives for phodynamic therapy (PDT) applications. In the second approach, nucleophilic substitution was employed to obtain an azide functionalized NCC derivative and PAMAM type dendrons were introduced afterwards via Click Chemistry. These hybrids were used to stabilize gold nanoparticles for catalysis in aqueous media.