Surface Modification of Textiles with Nanomaterials …
13
RF magnetron sputtering was used to deposit the copper on fabrics primarily to
confer antimicrobial properties. Moreover, use of argon plasma during deposition
induced cotton cellulose fragmentation and free radicals generation by means of
oxidation process. As a result, the amount of copper ions adhered to the surface of
the fabric greatly improved. From the obtained results, it was revealed that bacterial
growth drastically reduced for the highly Cu sputtered fabric. The mechanism behind
bacteria inhibition by Cu was claimed to be the generation of hydroxyl radicals and
oxygen molecules during redox reactions of Cu ions [78].
Instead of RF sputtering as discussed above, Laura Rio et al. came with DirectCurrent magnetron sputtering (DCMS)/Direct-Current pulsed magnetron sputtering (DCPMS) for Cu deposition against Staphylococcus aureus. Bacterial viability was assessed through four different techniques such as “mechanical detachment, microcalorimetry, direct transfer onto plates and stereomicroscopy” [79]. Here,
polyester was used as the substrate where the surface was sputtered with Cu by DC
magnetron sputtering. Time for Cu deposition was varied between 90, 120 and 160 s
in both the sputtering types. Akin to the above scenario, sputtered Cu by DCMS technique with greater time (160 s) showed efficient bactericidal activity which can be
evaluated from the combined results of direct transfer onto plates and stereochemistry
[79].
Even though cotton fabrics are promising to make wearable and flexible electronic
devices, there are challenges to form continuous films on a cotton fabric. The existing
literature on surface modified conductive fabrics addressed this limitation through
different modification techniques. Chuanmei Liu et al. sputtered an electrically conducting material like Ti and Ag on polyethylene terephthalate (PET) fabrics using
multi-target magnetron sputtering system. Extensive studies on electrical conductivity of the sputtered samples (Ti–Ag-Ti trilayer & Ti–Ag alloy) were carried out.
Out of those, deposition of Ti on a trilayer structure was deposited by RF sputtering,
whereas Ag was deposited by means of DC sputtering. Deposition of Ti–Ag alloy
films was also carried out using the same deposition parameters. In order to ensure
uniformity in deposition, the sample holder was rotated at a speed of 10 rpm. The
increase in Ag content in both the films resulted in an increase in the electrical conductivity. In particular, Ti–Ag alloy composition showed lesser electrical resistivity
(3.4 × 10
−7
m) than the trilayer configuration (5.1 × 10
−7
m) [80].
Potential of sputtering technique towards surface modification were utilized in
various applications. Carneiro et al. reported the photocatalytic and UV protection
activities of TiO 2 by pulsed magnetron sputtering on poly (lactic acid) fibres. High
pure titanium target of 99.9% was used for sputtering, where the oxygen flow was
allowed to the chamber to deposit TiO 2 on the fibre surface. The reason for employing
pulsed magnetron sputtering was to suppress the arc occurrence during deposition, as
arcs influence the stoichiometry in film growth ultimately influencing the optical and
electrical properties. For photocatalytic and UV protection applications, performance
metrices is mainly driven by its optical properties. In summary, it was concluded that
deposited TiO 2 films on fibre source exhibits an ultraviolet protection factor (UPF)
of 81.3% after washing compared to an unwashed fibre of 88.8% [81].
13
RF magnetron sputtering was used to deposit the copper on fabrics primarily to
confer antimicrobial properties. Moreover, use of argon plasma during deposition
induced cotton cellulose fragmentation and free radicals generation by means of
oxidation process. As a result, the amount of copper ions adhered to the surface of
the fabric greatly improved. From the obtained results, it was revealed that bacterial
growth drastically reduced for the highly Cu sputtered fabric. The mechanism behind
bacteria inhibition by Cu was claimed to be the generation of hydroxyl radicals and
oxygen molecules during redox reactions of Cu ions [78].
Instead of RF sputtering as discussed above, Laura Rio et al. came with DirectCurrent magnetron sputtering (DCMS)/Direct-Current pulsed magnetron sputtering (DCPMS) for Cu deposition against Staphylococcus aureus. Bacterial viability was assessed through four different techniques such as “mechanical detachment, microcalorimetry, direct transfer onto plates and stereomicroscopy” [79]. Here,
polyester was used as the substrate where the surface was sputtered with Cu by DC
magnetron sputtering. Time for Cu deposition was varied between 90, 120 and 160 s
in both the sputtering types. Akin to the above scenario, sputtered Cu by DCMS technique with greater time (160 s) showed efficient bactericidal activity which can be
evaluated from the combined results of direct transfer onto plates and stereochemistry
[79].
Even though cotton fabrics are promising to make wearable and flexible electronic
devices, there are challenges to form continuous films on a cotton fabric. The existing
literature on surface modified conductive fabrics addressed this limitation through
different modification techniques. Chuanmei Liu et al. sputtered an electrically conducting material like Ti and Ag on polyethylene terephthalate (PET) fabrics using
multi-target magnetron sputtering system. Extensive studies on electrical conductivity of the sputtered samples (Ti–Ag-Ti trilayer & Ti–Ag alloy) were carried out.
Out of those, deposition of Ti on a trilayer structure was deposited by RF sputtering,
whereas Ag was deposited by means of DC sputtering. Deposition of Ti–Ag alloy
films was also carried out using the same deposition parameters. In order to ensure
uniformity in deposition, the sample holder was rotated at a speed of 10 rpm. The
increase in Ag content in both the films resulted in an increase in the electrical conductivity. In particular, Ti–Ag alloy composition showed lesser electrical resistivity
(3.4 × 10
−7
m) than the trilayer configuration (5.1 × 10
−7
m) [80].
Potential of sputtering technique towards surface modification were utilized in
various applications. Carneiro et al. reported the photocatalytic and UV protection
activities of TiO 2 by pulsed magnetron sputtering on poly (lactic acid) fibres. High
pure titanium target of 99.9% was used for sputtering, where the oxygen flow was
allowed to the chamber to deposit TiO 2 on the fibre surface. The reason for employing
pulsed magnetron sputtering was to suppress the arc occurrence during deposition, as
arcs influence the stoichiometry in film growth ultimately influencing the optical and
electrical properties. For photocatalytic and UV protection applications, performance
metrices is mainly driven by its optical properties. In summary, it was concluded that
deposited TiO 2 films on fibre source exhibits an ultraviolet protection factor (UPF)
of 81.3% after washing compared to an unwashed fibre of 88.8% [81].