Encapsulation of inorganic particles with nanostructured cellulose

Inorganic- cellulose core-shell and hollow cellulose nanoparticles were prepared by self-encapsulation with regenerated cellulose in a poly(acrylic acid) hydrogel layer surrounding inorganic particle templates in N-methylmorpholine oxide (NMMO) (4-methylmorpholine N-oxide) monohydrate solution. The hydrogel layer surrounding the inorganic particle surface plays a decisive role in the core-shell formation. The core-shell nanostructures were characterized using TEM, SEM, and X-ray diffraction (XRD). The cellulose shell was found to be composed of cellulose spheres or nodules with dimensions of approximately 30 nm. Individual, regenerated cellulose nanoparticles were also synthesized by addition of nonsolvent under agitation to dilute solutions of cellulose dissolved in NMMO. The effects of the rate of addition of water (the nonsolvent) on the nanostructure, morphology and crystallinity of the regenerated cellulose nanoparticles were studied. The results indicate that the faster the water-addition rate, the smaller the cellulose nanoparticles formed.