Eco-friendly Surface Modification …
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zero capillary rise of water and 186 s of wet-out time compared to 61 mm capillary rise and 0 s wet-out time of 10 s plasma-treated samples. To analyse the effect
of ZnO adhesion on fabric after plasma treatment SEM, UPF and ICP-M analyses
were carried out. SEM analyses indicated that difference in zinc nanoparticles distribution. Untreated samples had unevenly distributed nanoparticles where the 10 s
plasma-treated samples were covered with a larger quantity of non-agglomerated
nanoparticles which was just opposite to 30 s plasma-treated sample as unevenly
agglomerated nanoparticles were present on the fibre surface. The UPF results and
ICP-MS analyses authenticated SEM analysis. The sample that was treated for 10 s
CF 4 plasma contained the highest quantity of Zn with highest UPF value (58.89),
whereas the untreated fabric had the lowest amount of zinc and minimum UPF value
(33.63). The amount of zinc and UPF values of H 2 O plasma-treated samples were
lower than 10 and 20 s CF 4 plasma-treated samples. These results clearly prove that
plasma treatment increases the adsorption of ZnO nanoparticles on cotton but only
up to 10 s treatment time. Smaller nanoparticles offer more protection against harmful UV radiation than larger particles; hence, although increased surface roughness
of 30 s plasma-treated samples had enhanced nanoparticles adhesion but still had
the lowest UPF value as the particles were agglomerated. The whiteness index of
cotton was enhanced after ZnO binding but decreased by long exposure to plasma
treatment even after ZnO nanoparticle functionalisation. The wash fastness of ZnO
functionalised samples was not at par as the UPF values decreased dramatically after
washing but since no binders were used to stabilise nanoparticles upon the surface
the obtained results were expected (Gorjanc et al. 2014).
4.3 Self-cleaning
Self-cleaning has been observed in plants like lotus as an important property. SEM
images of lotus leaf surface have shown a number of micro- to nanostructures which
do not allow particles to adhere and roll off water droplets from the surface picking
long dust particles to keep the leaf surface clean and dry even in swampy areas. The
technical expression of this basic idea has been patented by the trade name Lotus
effect® for such type of superhydrophobic self-cleaning products (Vigneshwaran
2009).
Application of crystalline TiO 2 as photocatalyst has increased tremendously over
the period of time due to the large surface area and better diffusibility of nanoparticles than macro-sized one. Commercially, nano-TiO 2 find widespread applicability
in water purification, air purification, disinfection but their usage in the textile surface
modification is still in early stages. With plasma pretreatment, a variety of negatively
charged functional groups like C–O, C = O, –COH, –COOH were introduced on the
fabric surface by the reaction between active O species of air and plasma-activated
carbon functional groups of textiles which helped in better bondability of Ti
+4 ion
of TiO 2. To develop the self-cleaning functionality of fabrics, Bozzi et al. activated
cotton, polyester, wool–polyamide with radiofrequency (RF) plasma (13.6 MHz,
553
zero capillary rise of water and 186 s of wet-out time compared to 61 mm capillary rise and 0 s wet-out time of 10 s plasma-treated samples. To analyse the effect
of ZnO adhesion on fabric after plasma treatment SEM, UPF and ICP-M analyses
were carried out. SEM analyses indicated that difference in zinc nanoparticles distribution. Untreated samples had unevenly distributed nanoparticles where the 10 s
plasma-treated samples were covered with a larger quantity of non-agglomerated
nanoparticles which was just opposite to 30 s plasma-treated sample as unevenly
agglomerated nanoparticles were present on the fibre surface. The UPF results and
ICP-MS analyses authenticated SEM analysis. The sample that was treated for 10 s
CF 4 plasma contained the highest quantity of Zn with highest UPF value (58.89),
whereas the untreated fabric had the lowest amount of zinc and minimum UPF value
(33.63). The amount of zinc and UPF values of H 2 O plasma-treated samples were
lower than 10 and 20 s CF 4 plasma-treated samples. These results clearly prove that
plasma treatment increases the adsorption of ZnO nanoparticles on cotton but only
up to 10 s treatment time. Smaller nanoparticles offer more protection against harmful UV radiation than larger particles; hence, although increased surface roughness
of 30 s plasma-treated samples had enhanced nanoparticles adhesion but still had
the lowest UPF value as the particles were agglomerated. The whiteness index of
cotton was enhanced after ZnO binding but decreased by long exposure to plasma
treatment even after ZnO nanoparticle functionalisation. The wash fastness of ZnO
functionalised samples was not at par as the UPF values decreased dramatically after
washing but since no binders were used to stabilise nanoparticles upon the surface
the obtained results were expected (Gorjanc et al. 2014).
4.3 Self-cleaning
Self-cleaning has been observed in plants like lotus as an important property. SEM
images of lotus leaf surface have shown a number of micro- to nanostructures which
do not allow particles to adhere and roll off water droplets from the surface picking
long dust particles to keep the leaf surface clean and dry even in swampy areas. The
technical expression of this basic idea has been patented by the trade name Lotus
effect® for such type of superhydrophobic self-cleaning products (Vigneshwaran
2009).
Application of crystalline TiO 2 as photocatalyst has increased tremendously over
the period of time due to the large surface area and better diffusibility of nanoparticles than macro-sized one. Commercially, nano-TiO 2 find widespread applicability
in water purification, air purification, disinfection but their usage in the textile surface
modification is still in early stages. With plasma pretreatment, a variety of negatively
charged functional groups like C–O, C = O, –COH, –COOH were introduced on the
fabric surface by the reaction between active O species of air and plasma-activated
carbon functional groups of textiles which helped in better bondability of Ti
+4 ion
of TiO 2. To develop the self-cleaning functionality of fabrics, Bozzi et al. activated
cotton, polyester, wool–polyamide with radiofrequency (RF) plasma (13.6 MHz,