By learning from nature and using bio-based building blocks we can engineer sustainable high-performance materials with improved functionality. However, the surface chemistry of nanocellulose must be well understood and controlled in order to optimize the interactions with liquids, ionic species and polymers. Water interactions play a crucial role in the processability and applicability of natural polymers and our research on nanocellulose has explored cellulose-water interactions across a range of material types (e.g. films, hydrogels, and dispersions). This talk will summarize approaches from our lab to tailor nanocellulose interactions with water specifically to enhance colloidal stability, rheological behaviour, emulsification and hydrophobicity. Tunability can be achieved either during nanocellulose production or through new surface modification routes. For example, we compare the properties of nanocellulose produced via hydrolysis with different acids or modified by polymer grafting, adsorption, or oligosaccharide precipitation. While primarily focused on cellulose nanocrystals, we have recently extended our tannic acid + alkylamine adsorption modification route to cellulose nanofibrils to improve their compatibility in epoxy resin composites. We believe that these efforts to control nanocellulose-water interactions and material assembly are crucial on the path towards the commercialization of greener next-generation technologies.