thicknesses (Figure 6-2). The core and the shell sizes were characterized as detailed in the

following, both by dynamic light scattering (DLS) and transmission electron microscopy (TEM)

after a preliminary staining step so that the core and the shell of the nanocapsules could be

distinguishable.

 Surfactants

 Oil 'C17Has /

 O~ ~ ~ ~ 3 CH3 N+ O OCiny
 O0 + C18H37-SI-OH C+ +
 Ethyl HC,O 3H Lecithin C71 HO O O
 Butyrate OTSC,H,, Tween-80 pmno=2
 Water HOI~l
 + heat
 H,C OCH





 Microemulsion

 Oil-filled silica nanocapsule



Figure 6-1. Oil-filled silica nanocapsule synthesis through initial hydrophobic core formation
 followed by hydrophilic silica shell formation after TMOS addition.


 al 
 Shell thickness Silca hel
 Increased b/ C iic hl
 (nanocapsule diameter /
 In the range 80-200 nm) cl Ethyl butyrate
 core





Figure 6-2. Description of the nanocapsule samples prepared using 0.07 wt % TMOS (a), 0.28 wt
 % TMOS (b), 0.44 wt % TMOS (c), and 0.88 wt % TMOS (d).