Fabrication of Superhydrophobic Textiles
209
this technique is that the inherent properties of textile more or less have been distorted because of this application technique [65, 66]. Different methods have been
adopted with minimum effect on intrinsic textile properties such as air permeability,
bending rigidity, hand feel, thermal and moisture management, appearance etc. with
greater durability and homogenous distribution of nanoparticles. Layer by Layer
self-assembly deposition is one of them in which electrostatic force of attraction is
basic reason to bind the nanoparticles at substrate. Zhao et al. [67] deposited silica
NPs using polyelectrolyte by layer by layer electrostatic self-assembly and created
nanoroughness at the surface. The post treatment of SiO 2 nanoparticles coated textile
was done with fluoroalkylsilane and superhydrophobic textile was developed water
contact angle higher than 150° and also the sliding angle of 10° was obtained. As the
surface morphology is also an important factor for the superhydrophobicity, therefore, it could be controlled by changing the number of layers on textiles and the water
contact angle of 170° could be achieved for textile modified with epichlorohydrin and
SiO
2 nanoparticles deposited by layer by layer assembly. Half of these nanoparticles
were 3-aminopropyltriethoxysiloxane and the remaining were 3-glycidoxypropyl
trimethoxysilane modified [68]. Nevertheless, the results are good but the technique
is limited due to higher production cost and the longer time for processing.
Though until now the silica nanoparticles have been most widely used inorganic
material to fabricate superhydrophobic textiles due to its inertness. But the textiles
treated with sol-gel synthesized SiO 2 are stiffer with less bending and comfort properties. Also decrease in mechanical properties like tear strength has been reported
in literature, due to cross-linking. But, even then the functionality is higher than the
demerits therefore, the practice to use these nanoparticles is still higher and the use
will be continued until the fabrication of some new material came into existence.
2.2.3 Plant Based Organic Repellents
Because the mostly used water repelling agents are not biodegradable and sustainable,
also, they are not easy to produce therefore, researchers have been trying to find out
natural, sustainable and cost effective materials to make textiles superhydrophobic.
Phytic acid containing six phosphate groups is naturally occurring component present
in many plant tissues, seeds, and also in legumes, grains and cereal. Several metal
ions Ce
III , Ag
I , Fe
III , Sn
IV and Zr
IV could have the ability to bind the phytic acid
just like a crosslinker and form the insoluble complex aggregations. This insoluble
metal complex aggregations were used to generate hierarchical nanoroughness at the
surface of cotton fabric. To enhance the superhydrophobic character further treatment
was done polydimethylsiloxane to make it superhydrophobic due to the its several
hydrophobic alkyl chain [69]. Schematic presentation of the whole process is given
in Fig. 8.
Researchers at Queensland University of Technology (QUT) have identified a
biodegradable and sustainable water proof coating going to commercialize soon.
They were analyzing possible applications for bagasse that is fibrous husk discarded
after sugar making. They realized that the lignin that is gigantic molecule could be
209
this technique is that the inherent properties of textile more or less have been distorted because of this application technique [65, 66]. Different methods have been
adopted with minimum effect on intrinsic textile properties such as air permeability,
bending rigidity, hand feel, thermal and moisture management, appearance etc. with
greater durability and homogenous distribution of nanoparticles. Layer by Layer
self-assembly deposition is one of them in which electrostatic force of attraction is
basic reason to bind the nanoparticles at substrate. Zhao et al. [67] deposited silica
NPs using polyelectrolyte by layer by layer electrostatic self-assembly and created
nanoroughness at the surface. The post treatment of SiO 2 nanoparticles coated textile
was done with fluoroalkylsilane and superhydrophobic textile was developed water
contact angle higher than 150° and also the sliding angle of 10° was obtained. As the
surface morphology is also an important factor for the superhydrophobicity, therefore, it could be controlled by changing the number of layers on textiles and the water
contact angle of 170° could be achieved for textile modified with epichlorohydrin and
SiO
2 nanoparticles deposited by layer by layer assembly. Half of these nanoparticles
were 3-aminopropyltriethoxysiloxane and the remaining were 3-glycidoxypropyl
trimethoxysilane modified [68]. Nevertheless, the results are good but the technique
is limited due to higher production cost and the longer time for processing.
Though until now the silica nanoparticles have been most widely used inorganic
material to fabricate superhydrophobic textiles due to its inertness. But the textiles
treated with sol-gel synthesized SiO 2 are stiffer with less bending and comfort properties. Also decrease in mechanical properties like tear strength has been reported
in literature, due to cross-linking. But, even then the functionality is higher than the
demerits therefore, the practice to use these nanoparticles is still higher and the use
will be continued until the fabrication of some new material came into existence.
2.2.3 Plant Based Organic Repellents
Because the mostly used water repelling agents are not biodegradable and sustainable,
also, they are not easy to produce therefore, researchers have been trying to find out
natural, sustainable and cost effective materials to make textiles superhydrophobic.
Phytic acid containing six phosphate groups is naturally occurring component present
in many plant tissues, seeds, and also in legumes, grains and cereal. Several metal
ions Ce
III , Ag
I , Fe
III , Sn
IV and Zr
IV could have the ability to bind the phytic acid
just like a crosslinker and form the insoluble complex aggregations. This insoluble
metal complex aggregations were used to generate hierarchical nanoroughness at the
surface of cotton fabric. To enhance the superhydrophobic character further treatment
was done polydimethylsiloxane to make it superhydrophobic due to the its several
hydrophobic alkyl chain [69]. Schematic presentation of the whole process is given
in Fig. 8.
Researchers at Queensland University of Technology (QUT) have identified a
biodegradable and sustainable water proof coating going to commercialize soon.
They were analyzing possible applications for bagasse that is fibrous husk discarded
after sugar making. They realized that the lignin that is gigantic molecule could be