Introduction
The sol–gel method is a novel procedure among solution
reactions which is based on the preparation of macromolecular
network through the typical hydrolysis of silicon alkoxide groups
followed by the condensation of the silanols. Now-a-days the
development of water repellent coatings on glass substrate
occupies most of the research agenda. Water repellent coatings
are useful for windshields of cars, surface of satellite antenna, antisnow
coating, hulls of ships and tubes or pipes [1–3]. Despite
having these fascinating properties and technological applications,
the structure of the silica network gets deteriorated with time due
to breaking of Si–O–Si bonds by nucleophilic attack of OH ions on
the Si atom [4]. Hence for a long-standing durability, the silica films
need to have water repellent (i.e. hydrophobic) properties. It is well
known that the wettability of a solid surface by water is governed
by the chemical properties of solid surface and its morphology [5].
Generally, surface chemical modification and roughening are the
two main approaches for the achievement of hydrophobic surface
[6–9]. Xiu et al. [10] prepared superhydrophobic durable selfcleaning
films by the incorporation of isobutyl-trimethoxysilane
into tetramethoxysilane causing hydrophobic isobutyl groups to
be present on the film surface, thus generating surface hydrophobicity.
Ogawa et al. [8] prepared superhydrophobic films with