Geoscience Reference
In-Depth Information
CO
3
O
4
Fe
3
O
4
3.8
nm
Modifier: C
9
COOH
Modifier: C
17
COOH
Superlattice = 2.8 nm twice of decanoic
acid's length
Superlattice = 3.8 nm twice of oleic
acid's length
Figure 10.54 Superlattices of modified Co
3
O
4
and Fe
3
O
4
synthesized by supercritical
hydrothermal method. The gap between the nanoparticles is twice the length of the organic
modifier carbon chain.
Source: Photograph Courtesy of T. Adschiri.
self-assembled nanoparticles is about 2.8 nm. Similarly, oleic acid has a carbon
chain length of 1.9 nm, but the distance between the oleic acid
modified magnetite
particles is about 3.8 nm. Thus, by choosing different types of modifiers with differ-
ent carbon chain lengths, the superlattice of the self-assembled nanoparticles can be
monitored precisely.
A large number of such superlattice structures have been obtained for modified
titania, zinc oxide, boehmite, cobalt spinels, and so on
[237
240]
. This area of
self-assembly of the hybrid organic
inorganic nanoparticles is growing quickly
and it has several advantages in obtaining the desired superlattice structures with
different packing arrangement for specific applications.
10.8 Hydrothermal Processing of Bioceramics
Bioceramics represent a broad spectrum of ceramic materials designed for chemical
compatibility and optimal mechanical strength with the physiological environment.
These materials are used for the repair and reconstruction of diseased or damaged
parts of the musculoskeletal system. Bioceramics may be bioinert (alumina, zirco-
nia), resorbable (tricalcium phosphate), bioactive (HAp), bioactive glasses, and glass
ceramics, or porous for tissue ingrowth (HAp-coated metals, alumina). Applications
include: replacements for hips, knees, teeth, tendons, and ligaments, and repair of
periodontal disease, maxillofacial reconstruction, augment and stabilization of the
jaw bone, spinal fusion, and bone fillers after tumor surgery
[257,258]
.
Table 10.6
