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M. Ashraf and S. Riaz
Superhydrophobic textiles have grabbed the greater attention of researchers and
textile engineers to be used in different fields of life [1–3] New gates were opened
for research on superhydrophobicity also known as physical self-cleaning after the
proposal of lotus leaves model unveiling that a particular surface topography and
low surface energy of material is required for a surface to be superhydrophobic.
Thus, micro and nano hierarchical nanoroughness is vital for physical self-cleaning
surfaces [4].
Thus recent trends to mimic the nature, have attracted the researchers to develop
superhydrophobic textiles with water contact angle greater than 150° and contact
angle hysteresis less than 10° using various techniques [5–7]. The loosely bound dirt,
dust, and soil could be attached with the rolling droplet thus causing self-cleaning
of material. Along with self-cleaning character such superhydrophobic surface are
also stain resistant due to less contact of stain with the surface and very high water
contact angle. Therefore, such surfaces could be used in areas [8–11] for water-oil
separation, anti-fogging, anticorrosion, and oil repellency etc.
Surfaces could be made hydrophobic by just lowering the surface energy of substrates. But, superhydrophobic surfaces need development of hierarchical roughness
along with lowering of surface energy [12]. In recent year, development of different
manipulation techniques played an important part to fabricate micro and nano surface roughness to create artificial superhydrophobic materials. Surface morphology
can be changed by different methods such as lithography, plasma treatment, solgel technique, layer by layer deposition, electrospinning, phase separation, template
synthesis and many more [4, 13, 14].
In this chapter, the hydrophobic fundamentals, switchable super hydrophobicity
and hydrophilicity have been described. Natural material based, organic and inorganic material based superhydrophobic textiles have been discussed in order to give
the overview of advancements in hydrophobicity and material used until now. There
is still a room for discovering the materials and application methods to make textile
superhydrophobic.
2 Water Repellency
The property due to which the water does not absorbed by the natural or synthetic
material when come in contact is called water repellency and it could be easily
rolled off or bounced back from the solid surface. The repellant character would
be determined by how much surface area of fabric is covered and what the angle
of impact is. Apart from synthetic materials, the natural materials do not have this
property and there is need to coat water repellent agents on the exterior of fabric or
sometimes infused in the fibers (Fig. 1).
M. Ashraf and S. Riaz
Superhydrophobic textiles have grabbed the greater attention of researchers and
textile engineers to be used in different fields of life [1–3] New gates were opened
for research on superhydrophobicity also known as physical self-cleaning after the
proposal of lotus leaves model unveiling that a particular surface topography and
low surface energy of material is required for a surface to be superhydrophobic.
Thus, micro and nano hierarchical nanoroughness is vital for physical self-cleaning
surfaces [4].
Thus recent trends to mimic the nature, have attracted the researchers to develop
superhydrophobic textiles with water contact angle greater than 150° and contact
angle hysteresis less than 10° using various techniques [5–7]. The loosely bound dirt,
dust, and soil could be attached with the rolling droplet thus causing self-cleaning
of material. Along with self-cleaning character such superhydrophobic surface are
also stain resistant due to less contact of stain with the surface and very high water
contact angle. Therefore, such surfaces could be used in areas [8–11] for water-oil
separation, anti-fogging, anticorrosion, and oil repellency etc.
Surfaces could be made hydrophobic by just lowering the surface energy of substrates. But, superhydrophobic surfaces need development of hierarchical roughness
along with lowering of surface energy [12]. In recent year, development of different
manipulation techniques played an important part to fabricate micro and nano surface roughness to create artificial superhydrophobic materials. Surface morphology
can be changed by different methods such as lithography, plasma treatment, solgel technique, layer by layer deposition, electrospinning, phase separation, template
synthesis and many more [4, 13, 14].
In this chapter, the hydrophobic fundamentals, switchable super hydrophobicity
and hydrophilicity have been described. Natural material based, organic and inorganic material based superhydrophobic textiles have been discussed in order to give
the overview of advancements in hydrophobicity and material used until now. There
is still a room for discovering the materials and application methods to make textile
superhydrophobic.
2 Water Repellency
The property due to which the water does not absorbed by the natural or synthetic
material when come in contact is called water repellency and it could be easily
rolled off or bounced back from the solid surface. The repellant character would
be determined by how much surface area of fabric is covered and what the angle
of impact is. Apart from synthetic materials, the natural materials do not have this
property and there is need to coat water repellent agents on the exterior of fabric or
sometimes infused in the fibers (Fig. 1).