There is an increasing interest in developing eco-friendly materials to prepare new materials for various applications. Within these efforts, cellulose nanocrystals (CNCs) are gaining increasing popularity due to their abundance, renewability and biodegradability. They display unique properties such as a high anisotropy coupled with a longitudinal twist that enables them to selfassemble in suspension into a chiral nematic phase, and a high amount of reactive surface hydroxyl groups that can be used to introduce virtually any surface functionality. Understanding the thermodynamic interactions of cellulose nanomaterials with their environment is important to understand the forces behind their self-organization and their co-organization with other compounds, and to be able to use self-assembly to form new functional multicomponent materials. In addition, understanding the thermodynamic interactions driving adsorption on cellulose nanomaterials is required for developing new drug delivery systems based on CNCs, for their use in ion exchange applications, and for the removal of pollutants from water. To date the number of studies reporting the thermodynamics of interaction on nanocellulose surfaces is scarce, and they also tend to focus on interactions with a variety of cellulose substrates making direct comparison difficult. In this thesis, isothermal titration calorimetry (ITC) was employed as the main technique to study the thermodynamics of interaction on nanocellulose surfaces. Only a few nanotechnology studies have been reported in the literature using this technique, and this work represents an important development for the use of ITC in …