Although studies of this kind
do not fully mimic the natural conditions of moisture
loss, the lower the size of the particles, the
greater is the barrier for evaporation, whereas the
higher the size is, the more the amount of water
that will be evaporated. Figure 1 compares this
effect based on the different structure of the adhesive
microparticle/nanoparticle layer on the skin.
When applying lipid particles onto the skin, a
film layer will be formed, having a surface area
which is dependent on the particle size. The space
filled with air in a layer of optimal packing density
is independent on the particle size, which is considered
to be 24% if assuming a three-dimensional
hexagonal packing of ideal spherical-like particles.
However, comparing a layer of nanoparticles