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M. Singh et al.
transmittance of plasma-treated and silver-sputtered fabrics increased gradually from
less than 4% in the UV-B region for run 1 and grew to a minimum of 0.2% for a run 6
compared to 7–10% transmittance of untreated samples indicating that the resistance
of an untreated fabric to UV rays was weak. UPF values increased to 264.34 for the
silver-sputtered cotton fabric in run 6 that was 300 s and 0.005 gas pressure compared to 11.71 of untreated. These results indicate that untreated cotton had a high
UV transmittance and low UPF, while the sputtered fabrics had a high UPF and low
UV transmittance which increased with plasma treatment time. These results present
plasma and nanoparticles as a promising technology for developing UV protection
textiles (Shahidi and Ghoranneviss 2016). In one of the studies, scientists treated cotton samples in low-pressure inductively coupled radiofrequency plasma system for
10, 20 and 30 s to increase their adsorptive properties. Plasma-treated samples were
functionalised with 3% ZnO nanoparticles for enhancing UV protection properties of
the fabric. The XPS survey spectra depicted a higher O/C ratio along with increased
C–O bonds and decreased C–C bonds due to the incorporation of oxygen-containing
functional groups on the cellulosic surface. SEM images also clearly showed the
increasing percentage of ZnO nanoparticles on the plasma-treated surface with even
distribution and no agglomerates after more prolonged plasma treatment. Zinc oxide
nanoparticles functionalised cotton fabric showed excellent UV protection with a
UPF value of 33.63, but it increased twofold in case of 30 s plasma-treated sample
which proved that more prolonged plasma treatment increased the content of ZnO
nanoparticles on the fibres. The durability of plasma and nanoparticle treatment was
assessed in 10 washing cycles. After one wash, UPF value were not changed extensively, but after ten wash there was a significant decrease in UPF values although
the values remained highest for 30 s plasma-treated samples (Jazbec et al. 2015).
CF 4 plasma has also been used to increase the adhesion of ZnO nanoparticles and in
turn, generate good UV protective properties on cotton fabrics. Gorjanc et al. treated
cotton fabrics in weakly ionised gaseous plasma created in a mixture of CF 4 and H 2 O
gas with an electrodeless RF discharge for a treatment time of 10, 20 and 30 s. The
researchers claimed that although CF 4 gas is typically associated with hydrophobicity when used in combination with oxygen it increases the polymer etch rates. To
confirm the hypothesis that treatment with moist CF 4 plasma gives better etch results,
a series of characterisation studies were carried out. Optical emission spectroscopy
(OES) study reveals that the intensity of CO molecular bands was much lower for
CF 4 plasma-treated sample compared to H 2 O plasma-treated sample indicating that
better etching and oxidation was achieved in the earlier plasma gas. SEM images
showed a smooth exterior of untreated fibrils compared to rough topography of 30 s
plasma-treated cotton fibres. SEM images of H 2 O plasma-treated sample also showed
morphological changes but the etching effect was less pronounced than CF 4 plasmatreated fibres. The XPS spectra of 30 s plasma-treated sample detected the measurable
amount of F along with a decreased O/C ratio, whereas all the other samples were free
of it suggesting of its hydrophobic nature. Wettability and absorptivity measurements
performed on untreated and CF 4 plasma-treated cotton samples also backed the XPS
results as the 30 s CF 4 plasma-treated samples displayed hydrophobic character with
M. Singh et al.
transmittance of plasma-treated and silver-sputtered fabrics increased gradually from
less than 4% in the UV-B region for run 1 and grew to a minimum of 0.2% for a run 6
compared to 7–10% transmittance of untreated samples indicating that the resistance
of an untreated fabric to UV rays was weak. UPF values increased to 264.34 for the
silver-sputtered cotton fabric in run 6 that was 300 s and 0.005 gas pressure compared to 11.71 of untreated. These results indicate that untreated cotton had a high
UV transmittance and low UPF, while the sputtered fabrics had a high UPF and low
UV transmittance which increased with plasma treatment time. These results present
plasma and nanoparticles as a promising technology for developing UV protection
textiles (Shahidi and Ghoranneviss 2016). In one of the studies, scientists treated cotton samples in low-pressure inductively coupled radiofrequency plasma system for
10, 20 and 30 s to increase their adsorptive properties. Plasma-treated samples were
functionalised with 3% ZnO nanoparticles for enhancing UV protection properties of
the fabric. The XPS survey spectra depicted a higher O/C ratio along with increased
C–O bonds and decreased C–C bonds due to the incorporation of oxygen-containing
functional groups on the cellulosic surface. SEM images also clearly showed the
increasing percentage of ZnO nanoparticles on the plasma-treated surface with even
distribution and no agglomerates after more prolonged plasma treatment. Zinc oxide
nanoparticles functionalised cotton fabric showed excellent UV protection with a
UPF value of 33.63, but it increased twofold in case of 30 s plasma-treated sample
which proved that more prolonged plasma treatment increased the content of ZnO
nanoparticles on the fibres. The durability of plasma and nanoparticle treatment was
assessed in 10 washing cycles. After one wash, UPF value were not changed extensively, but after ten wash there was a significant decrease in UPF values although
the values remained highest for 30 s plasma-treated samples (Jazbec et al. 2015).
CF 4 plasma has also been used to increase the adhesion of ZnO nanoparticles and in
turn, generate good UV protective properties on cotton fabrics. Gorjanc et al. treated
cotton fabrics in weakly ionised gaseous plasma created in a mixture of CF 4 and H 2 O
gas with an electrodeless RF discharge for a treatment time of 10, 20 and 30 s. The
researchers claimed that although CF 4 gas is typically associated with hydrophobicity when used in combination with oxygen it increases the polymer etch rates. To
confirm the hypothesis that treatment with moist CF 4 plasma gives better etch results,
a series of characterisation studies were carried out. Optical emission spectroscopy
(OES) study reveals that the intensity of CO molecular bands was much lower for
CF 4 plasma-treated sample compared to H 2 O plasma-treated sample indicating that
better etching and oxidation was achieved in the earlier plasma gas. SEM images
showed a smooth exterior of untreated fibrils compared to rough topography of 30 s
plasma-treated cotton fibres. SEM images of H 2 O plasma-treated sample also showed
morphological changes but the etching effect was less pronounced than CF 4 plasmatreated fibres. The XPS spectra of 30 s plasma-treated sample detected the measurable
amount of F along with a decreased O/C ratio, whereas all the other samples were free
of it suggesting of its hydrophobic nature. Wettability and absorptivity measurements
performed on untreated and CF 4 plasma-treated cotton samples also backed the XPS
results as the 30 s CF 4 plasma-treated samples displayed hydrophobic character with