Size/Shape – Property Relationships of Non - Carbonaceous Inorganic Nanoparticles and their Environmental Implications - Environmental and Human Health Impacts of Nanotechnology - page 93

(a)

{100} {100}

(b)

d 100

d 100

d 110

d 110

(c)

Figure 3.6 (a) High resolution TEM images of a nanoparticle before dissolution (left) and
a nanoparticle after 2 hours of dissolution (right). Note how the sizes of the {110} faces have
increased. (b) Schematic diagrams of the distances measured on particles to determine
whether the change in {110} size is statistically signifi cant. (c) Distance ratios of d 100 /d 110
before and after dissolution, along with mean values and 95% confi dence intervals. As the
{110} face size increases after 2 hours of dissolution, the value of the ratio increases.

the small size of the nanocrystals. As mentioned earlier, the modifi ed Kelvin equa-
tion indicates that dissolution is more thermodynamically favoured for smaller
particles. Also, due to their size, nanocrystals have a larger fraction of their atoms
at corners and edges than bulk crystals. Such undercoordinated atoms are more
active in dissolution than ones from fl at surfaces. Nanoparticle morphology may