Effects of Solvent Polarity on Nanostructure Formation of Spray-Dried TEMPO-Oxidized Cellulose Nanofiber Particles

One of the main challenges in practical applications of nanocellulose-based particles is the maintenance of their high surface area and chemical properties during particle formation in the drying process. In this study, we report the preparation of nanostructured 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO)-oxidized cellulose nanofiber (TOCN) particles via a spray-drying process without changing their chemical functionalization. The physicochemical properties of TOCN particles prepared by various types and concentrations of organic solvents were investigated. The resulting particles possessed a high zeta-potential value (-51 to -63 mV). We found that the formation of the porous structure could be realized by controlling the solvent polarity, which effectively increased the surface area to 222 m(2)/g and led to a good adsorption capacity for macromolecules such as lysozyme protein (> 3200 mg/g). These results show that this method has a wide range of potential applications, e.g., drug delivery agents, adsorbents, encapsulation, and composite technologies.