540
V. S. Simi et al.
9.4 Functionalization Using Tetrahedral Amorphous Carbon
(Ta-C)
Diamond-like carbon (DLCs) with “higher sp
3 contents are termed as tetrahedral
amorphous carbon (ta-C) and their hydrogenated analogue, ta-C:H [23, 121–127].
Tetrahedral amorphous carbon (ta-C) is extensively used as a coating material
because of its properties such as high hardness, chemical inertness, superior wear
resistance and low coefficient of friction comparable to diamond [128]. It has been
demonstrated that the exceptional mechanical behavior of ta-C is mostly determined
by its high percentage of sp
3 hybridization [129]. These properties make it ultimate
for wear resistance on automotive components, cutting tools, aerospace components
and biomedical applications. Mohan et al. [130] fabricated nanotubes on Ti–6Al–7Nb
alloy by anodisation and filled tetrahedral amorphous carbon (ta-C) into nanotubes by
cathodic arc evaporation method and characterized them for their nanoscale features”.
FESEM image of an anodic TiO 2 nanotube array (TNT) obtained after anodisation
of Ti–6Al–7Nb for 1 h at 30 V is shown in Fig. 21a. In this image, high degree of
ordering of tubes can be seen. Figure 21b–f “shows the FESEM images of TNT filled
with tetrahedral amorphous carbon (ta-C) for 0.5, 1, 2, 5 and 10 min, respectively.
As can be seen from Fig. 21b, in 0.5 min, filling of ta-C takes place in inter-tubular
space and pores. After 1 min, ta-C filled into inter-tubular space and pores formed
network like growth of carbon can be seen from Fig. 21c. In Fig. 21d, 2 min filling,
shows nodular like structure. Similarly, after 5 min in Fig. 21e, uniform spherical
shape morphology can be seen which has covered the tubular pores and porous space.
Further increase in deposition time to 10 min, the formed spherical morphology fuse
together and completely covers the TNT which can be seen in Fig. 21f. From the
figures, it can be seen that the gradual filling of the TNT by ta-C is taking place with
increasing deposition time. The roughness values decrease due to an increase in the
filling time resulting in a smoother layer. To demonstrate the filling rate of nanotubes
3D analyses was carried out on TNT and ta-C filled TNT samples. Figure 22a–f
shows the 3D images obtained from FESEM images for single nanotube of TNT and
ta-C filled TNT samples at 0.5, 1, 2, 5 and 10 min, respectively”.
9.5 Loading of Quercetin and Chitosan into Nanotubes
for Drug Delivery
Many researchers have investigated titanium nanotubes based drug-releasing
implants (DRIs) in medical fields, such as “orthopedic implants, dental implants,
vascular (coronary) stents, bone tissue engineering and localized cancer therapy” [33, 131, 132]. “Several therapeutic agents such as antibiotics, antifungal,
anti-inflammatory, anticancer drugs, bone proteins, peptides, enzymes, vitamins,
hormones, genes, antibodies, neurotransmitters, drug nanocarriers and nanoparticles have been applied in order to employ a wide range of therapies into titanium
V. S. Simi et al.
9.4 Functionalization Using Tetrahedral Amorphous Carbon
(Ta-C)
Diamond-like carbon (DLCs) with “higher sp
3 contents are termed as tetrahedral
amorphous carbon (ta-C) and their hydrogenated analogue, ta-C:H [23, 121–127].
Tetrahedral amorphous carbon (ta-C) is extensively used as a coating material
because of its properties such as high hardness, chemical inertness, superior wear
resistance and low coefficient of friction comparable to diamond [128]. It has been
demonstrated that the exceptional mechanical behavior of ta-C is mostly determined
by its high percentage of sp
3 hybridization [129]. These properties make it ultimate
for wear resistance on automotive components, cutting tools, aerospace components
and biomedical applications. Mohan et al. [130] fabricated nanotubes on Ti–6Al–7Nb
alloy by anodisation and filled tetrahedral amorphous carbon (ta-C) into nanotubes by
cathodic arc evaporation method and characterized them for their nanoscale features”.
FESEM image of an anodic TiO 2 nanotube array (TNT) obtained after anodisation
of Ti–6Al–7Nb for 1 h at 30 V is shown in Fig. 21a. In this image, high degree of
ordering of tubes can be seen. Figure 21b–f “shows the FESEM images of TNT filled
with tetrahedral amorphous carbon (ta-C) for 0.5, 1, 2, 5 and 10 min, respectively.
As can be seen from Fig. 21b, in 0.5 min, filling of ta-C takes place in inter-tubular
space and pores. After 1 min, ta-C filled into inter-tubular space and pores formed
network like growth of carbon can be seen from Fig. 21c. In Fig. 21d, 2 min filling,
shows nodular like structure. Similarly, after 5 min in Fig. 21e, uniform spherical
shape morphology can be seen which has covered the tubular pores and porous space.
Further increase in deposition time to 10 min, the formed spherical morphology fuse
together and completely covers the TNT which can be seen in Fig. 21f. From the
figures, it can be seen that the gradual filling of the TNT by ta-C is taking place with
increasing deposition time. The roughness values decrease due to an increase in the
filling time resulting in a smoother layer. To demonstrate the filling rate of nanotubes
3D analyses was carried out on TNT and ta-C filled TNT samples. Figure 22a–f
shows the 3D images obtained from FESEM images for single nanotube of TNT and
ta-C filled TNT samples at 0.5, 1, 2, 5 and 10 min, respectively”.
9.5 Loading of Quercetin and Chitosan into Nanotubes
for Drug Delivery
Many researchers have investigated titanium nanotubes based drug-releasing
implants (DRIs) in medical fields, such as “orthopedic implants, dental implants,
vascular (coronary) stents, bone tissue engineering and localized cancer therapy” [33, 131, 132]. “Several therapeutic agents such as antibiotics, antifungal,
anti-inflammatory, anticancer drugs, bone proteins, peptides, enzymes, vitamins,
hormones, genes, antibodies, neurotransmitters, drug nanocarriers and nanoparticles have been applied in order to employ a wide range of therapies into titanium