Pluronic® F127 nanoparticles were loaded with citronella essential oil (CEO) and then covered with chitosan-sodium alginate polyelectrolyte complex (PEC). The system was characterized according to size, zeta potential and stability over time. Dynamic light scattering (DLS) in different proportions of water/ethanol as a dispersive medium was important in confirming that PEC covered the F127 nanoparticles. Infrared spectroscopy also indicated interaction of F127 with PEC. The nanoparticle size evaluated by transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM) corroborated the value observed in DLS (hydrodynamic radius (RH) range of 100-200 nm). Encapsulation efficiency of 80% for CEO was determined by UV-Vis spectroscopy. The release profile of the CEO was evaluated in phosphate buffer saline (PBS) containing 20% of ethanol and in simulated sweat fluid, achieving 74 and 81%, respectively. The releasing mechanism fitted the Korsmeyer-Peppas mathematical model, indicating Fickian diffusion behavior for both studied media.

The barrier and mechanical properties of polymer matrices are affected by the polymer crystallization kinetics and the incorporation of nanoparticles can modify the nucleation density as well as the rate and mechanism of crystallization. In this study, a nanocomposite of poly(lactic acid) (PLA) containing cellulose nanocrystals (CNC) was prepared in order to evaluate the effect of the CNC content on the crystallization kinetics of the polymer matrix. Dimethylformamide, a solvent of PLA, was used to replace the aqueous medium for the dispersion of the CNC, to facilitate the preparation of PLA films with dispersed CNC. Higher levels of CNC in the films induced an increase in the crystallization rate and reduced the degree of crystallinity without affecting the dimensions of the crystal lattice. In conclusion, the incorporation of CNC into PLA influences the crystallization kinetics, which significantly affects the PLA processing conditions.