Tese_Tânia Vieira.pdf - Ubi Thesis

Chapter III – Results and Discussion
Figure 5 – SEM images of AgNPs produced by chemical reduction with NaBH 4 , with a concentration of AgNO 3
of 0.1 M (A); 0.001 M (B); 0.01 M (C and D); and AgNPs produced by chemical reduction with C 6 H 8 O 6 with a
concentration of AgNO 3 of 0.01 M (E and F).
According to Badway and colleagues, the high surface area to volume ratio of the
nanoparticles, results in a high reactivity which leads to particle aggregation and settling. Such
events can be avoided if particles are protected by a capping agent, like surfactants and
polymers, that provide colloidal stability through electrostatic or steric repulsion (Badawy et al.
2010). Therefore, the second step of this work was to produce chitosan/dextran nanoparticles.
These type of nanoparticles were produced by ionotropic gelation between the negatively
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