Nanocellulose: A study of the physicochemical properties and morphology

Cellulose nanocrystals (CNCs) are highly crystalline, rod-like nanomaterials whose anisotropic shape, abundant surface hydroxyl groups, and ability to form chiral nematic liquid phases make them uniquely suited for sustainable high-performance materials. Yet despite their promise, CNC structure-property relationships remain insufficiently understood, particularly regarding how surface chemistry, hydrogen-bond networks, surface-sulfur composition, and environmental or processing conditions drive self-assembly, mechanical behavior, and interactions with other biomolecular systems. These knowledge gaps limit the rational design of CNC-based materials for advanced technologies, including solid-state devices, responsive composites, and additive manufacturing. This work provides a systematic multi-scale investigation of CNC chemistry and hierarchical organization, establishing mechanistic connections between molecular-level interactions and macroscopic material behavior. The first component of this work resolves how subtle variations in the CNC interfacial environment influence evaporation-induced self-assembly. By probing the effects of substrate chemistry, surface hydrogen bonding interactions, and oxidative modulations of CNC crystallinity, this first part shows that CNC alignment and final film morphology are highly sensitive to the physicochemical context in which self-assembly occurs. These findings underscore the importance of precise control over interfacial and processing conditions when engineering CNC-based structural or photonic films. The second component evaluates ionic liquid (IL) interactions with CNCs to address intrinsic limitations in flexibility, thermal stability, and ionic transport. Through analysis of IL-CNC hydrogen bonding and counterion-specific interactions, this work demonstrates that ILs act as tunable plasticizers that modulate CNC crystallinity, chain mobility, and dielectric behavior without significantly compromising the native order. The third component advances CNC functionalization by covalently incorporating polymerized ionic liquid (PIL) units via a click-chemistry-based strategy. Introducing permanent ionic functionalities enables the formation of CNC-PIL hybrids with enhanced ionic conductivity and a modified amorphous-crystalline organization. This work clarifies how this ionic functionality governs nanoscale phase behavior and transport properties, providing a rational basis for the formation of CNC-based ion-conductive materials. The final component integrates CNC-IL systems into polysaccharide matrices, focusing on agarose, to design moisture-responsive shape-morphing biocomposites. By mechanistically evaluating how CNC reinforcement, IL-mediated plasticization, and water-retention dynamics couple to drive stress generation and bending behavior, this work demonstrates strategies for tailoring programmable deformation in bio-derived materials suitable for extrusion-based fabrication and soft-matter applications. Collectively, this study establishes a cohesive framework linking CNC chemistry, surface interactions, hierarchical assembly, and emergent functional behavior. By bridging molecular-scale understanding with material-level performance, this work advances CNCs from promising natural nanomaterials to precision-engineered components that support sustainable technologies.