The surface properties of cellulose nanocrystals are key elements in many applications and they can be modified or tuned either by chemical modifications or physical adsorption. In the latter case, the final properties of the cellulose nanocrystals are driven by the adsorption behaviour of the adsorbing species. In an ideal thermodynamic approach, adsorption is expected to be associate with desorption process to reach thermodynamic equilibrium. However, in many cases in practice, desorption process, if any, occurs at far larger time scale than adsorption suggesting irreversible adsorption. As a consequence the process is not thermodynamically but kinetically controlled. In this paper, we investigated the kinetics of adsorption processes of polyelectrolytes, neutral polysaccharides (hemicelluloses) and cationic nanoparticles on cellulose nanocrystals model surfaces. The adsorption kinetic was monitored by quartz-crystal microbalance with dissipation (QCM-D). The adsorption of polymers and nanoparticles under flow at different concentrations did not result in the same surface concentration, which evidenced the kinetically-controlled process. In an attempt to describe the binding process, adsorption data were fitted to a kinetic model comprising the contribution of adsorption onto uncovered CNC and the contribution of adsorption on saturated surface. Kinetic studies evidenced the presence of different adsorption regimes according to the polymers or particles structures. Energy dissipation changes during the adsorption process were also examined by QCM-D for the different polymers and nanoparticles as a function of chemical structures and adsorption regimes. Finally the morphologies and the surface energies of the coated cellulose nanocrystals were determined to investigate the surface properties after adsorption.<br/>

Kinetic of polymers and nanoparticles adsorption on cellulose nanocrystal surfaces

255th National Meeting (2018)

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