Page 84 - Environmental Nanotechnology Applications and Impacts of Nanomaterials

70 Principles and Methods

(a)
(b)

(c)

Figure 3.29 (a) TEM images of 4.6 aspect ratio gold nanorods, (b) shape-separated
13 aspect ratio gold nanorods, and (c) shape-separated 18 aspect ratio gold nanorods [126].

is not yet completely understood. Replacement of citrate by CTAB in the
seed formation step and the use of a binary surfactant mixture improve
the procedure in terms of selectivity in particle shape and amount of gold
nanorods [129]. A similar procedure with silver nitrate allows the forma-
tion of silver nanorods and nanowires [130]. More generally, templating
syntheses involving surfactants have been used to control the morphology
of various metallic materials [127].
Silver nanowires were also obtained by an intriguing sono-assisted
self-reduction template process [131]. A solution of a suitable precur-
sor, the adduct Ag(hexafluoro-acetylacetone)-tetraglyme (tetraglyme
2,5,8,11,14-pentaoxadecane) in ethanol/water 1:1 is loaded into the
pores of an anodic aluminum oxide membrane consisting of ordered
hole arrays of 200 nm in diameter and 60
m in thickness, which is