2
D. K. Subbiah et al.
chemical precursors and physical conditions can result in versatile nanostructures that
finds utility in a range of applications [1]. In recent years, materials scientists have
taken a paradigm shift and concentrated on engineering nanomaterials, where they
intentionally design and develop synthetic materials with the desired physiochemical properties for a targeted purpose or function [2]. Nanomaterials have greatly
enhanced the functional properties of matter, making them the most sought-after
candidate for biocompatible applications like drug delivery [3], nanosensors [4] and
nanomaterial modified textiles [5].
The demand for highly durable and functional garments has resulted in a growing
necessity for textiles modified with nanomaterials. Nanomaterials offer enhanced
functionalities to textiles such as enhancement of oil/water repellence [6], ultraviolet
(UV) blocking ability [7], reduction of wrinkles [8], elimination of static charge build
up [9], continuous monitoring of bodily functions and metabolism [10], rehabilitation, toxicity reduction [11], long term durability, and environmental impact without
compromising their flexibility or comfort. This new approach has opened up several windows in the wearable and flexible technologies including garments, which
is capable of sensing and responding to environmental stimuli including mechanical, chemical, electrical, thermal, optical, or magnetic sources. Studies have been
conducted on electronic and photonic nanomaterials [12] integrated with textiles
especially, to validate their plausible potential in sensing, optical displays [13], and
drug delivery applications where they are examined in terms of their performance,
durability, and connectivity.
Cotton is widely preferred by textile manufacturers towards realizing wearable
textiles owing to its high absorbing capacity, chemically adaptable surface and flexibility. Notwithstanding these merits, the fibres of cotton fabrics have lower strength
and easily flammable nature. As a result, such exacerbating properties of natural
cotton imparts greater limitations in (i) electronic applications (where repeatability
and durability at end user); (ii) antibacterial actions of cotton relatively decreases
as a consequence of laundering [14]. To overcome these challenges with cotton,
synthetic fibres have emerged as the other alternatives. It has been proved to have
better anti-microbial and stain-resistance properties but at the cost of comfort. Thus,
nanoengineered fabrics would plausibly stand as a conglomeration of the merits of
both natural and synthetic fibres, while furnishing novel functionalities.
Chemical vapour deposition (CVD) and physical vapour deposition (PVD) techniques offer several advantages for surface modification of textiles [15]. Among the
two techniques, PVD has proven to furnish high adherent coatings. PVD is a thin
film coating technique, which involves condensation of vaporized thin film materials
over the substrate/textile. PVD is generally conducted in vacuum, thereby offering
high purity and uniformly coated thin films owing to the increased mean free path
of the sputtered atoms. PVD techniques include cathode arc deposition, pulsed laser
deposition, electron beam evaporation, evaporative deposition, sputtering, ion plating, thermal evaporation, and enhanced sputtering. The general mechanism in PVD
techniques involve evaporation of the solid thin film materials to be coated onto the
substrate by heat or ion bombardment (sputtering) [16]. Simultaneously, a reactive
D. K. Subbiah et al.
chemical precursors and physical conditions can result in versatile nanostructures that
finds utility in a range of applications [1]. In recent years, materials scientists have
taken a paradigm shift and concentrated on engineering nanomaterials, where they
intentionally design and develop synthetic materials with the desired physiochemical properties for a targeted purpose or function [2]. Nanomaterials have greatly
enhanced the functional properties of matter, making them the most sought-after
candidate for biocompatible applications like drug delivery [3], nanosensors [4] and
nanomaterial modified textiles [5].
The demand for highly durable and functional garments has resulted in a growing
necessity for textiles modified with nanomaterials. Nanomaterials offer enhanced
functionalities to textiles such as enhancement of oil/water repellence [6], ultraviolet
(UV) blocking ability [7], reduction of wrinkles [8], elimination of static charge build
up [9], continuous monitoring of bodily functions and metabolism [10], rehabilitation, toxicity reduction [11], long term durability, and environmental impact without
compromising their flexibility or comfort. This new approach has opened up several windows in the wearable and flexible technologies including garments, which
is capable of sensing and responding to environmental stimuli including mechanical, chemical, electrical, thermal, optical, or magnetic sources. Studies have been
conducted on electronic and photonic nanomaterials [12] integrated with textiles
especially, to validate their plausible potential in sensing, optical displays [13], and
drug delivery applications where they are examined in terms of their performance,
durability, and connectivity.
Cotton is widely preferred by textile manufacturers towards realizing wearable
textiles owing to its high absorbing capacity, chemically adaptable surface and flexibility. Notwithstanding these merits, the fibres of cotton fabrics have lower strength
and easily flammable nature. As a result, such exacerbating properties of natural
cotton imparts greater limitations in (i) electronic applications (where repeatability
and durability at end user); (ii) antibacterial actions of cotton relatively decreases
as a consequence of laundering [14]. To overcome these challenges with cotton,
synthetic fibres have emerged as the other alternatives. It has been proved to have
better anti-microbial and stain-resistance properties but at the cost of comfort. Thus,
nanoengineered fabrics would plausibly stand as a conglomeration of the merits of
both natural and synthetic fibres, while furnishing novel functionalities.
Chemical vapour deposition (CVD) and physical vapour deposition (PVD) techniques offer several advantages for surface modification of textiles [15]. Among the
two techniques, PVD has proven to furnish high adherent coatings. PVD is a thin
film coating technique, which involves condensation of vaporized thin film materials
over the substrate/textile. PVD is generally conducted in vacuum, thereby offering
high purity and uniformly coated thin films owing to the increased mean free path
of the sputtered atoms. PVD techniques include cathode arc deposition, pulsed laser
deposition, electron beam evaporation, evaporative deposition, sputtering, ion plating, thermal evaporation, and enhanced sputtering. The general mechanism in PVD
techniques involve evaporation of the solid thin film materials to be coated onto the
substrate by heat or ion bombardment (sputtering) [16]. Simultaneously, a reactive