possesses the most uniform particle size (the size is mainly in
the range of 70–80 nm in diameter) among those CTAB-assisted
samples. Third, in the beginning, the presence of CTAB makes the
mean size increased (91 vs. 22 nm for 1.5CTAB and 0CTAB, respec-tively), but then, it induces a gradual mean size decrease with
increasing CTAB concentration (91, 75, and 49 nm for 1.5CTAB,
2.2CTAB, and 2.9CTAB, respectively). This interesting feature will
be explained in Section3.2