10
D. K. Subbiah et al.
confining those metals to nano scale offers much more conductivity (e.g. gold, silver).
In general, metals are defined as solid, hard and mechanically stable materials. In
transistor technology, especially in metal oxide semiconductor field effect transistor
(MOSFET), metals were used as the gate material. This was because the material
that was employed as the gate in the transistor must have high conductivity, with
the applied voltage between terminal (source) and metal (gate) regulates the channel
voltage. Metals are also found in liquid form (e.g. mercury, gallium), offering both
metallic and fluidic properties [54].
Moreover, metals provide appreciable deformable nature wherein it could retain
their function under stretching, bending and twisting action. Such attractive properties facilitate the fabrication of flexible electronic devices. Deploying such electronic
devices (e.g. sensor, antenna) interconnected by metal and deformable on a flexible
substrate like textile, plastic would pave a way to attain a benchmark in wearable
electronics.
2.5 Multifunctional Textiles
Textile is one of the basic commodities, which has been historically used for clothing
over centuries. In this techno-era, attempts have been made to make it smart for multitasking. Improvisation of traditional fabric in properties such as hydrophobicity [55]
(dirt-free), conductivity [56], antimicrobial activity [57], ultraviolet resistance [58],
flame retardancy [59] and stimuli-responsiveness have been reported so far. Modified
textile with super hydrophobicity results in self-cleaning [60] properties could be
used to separate oil-water mixtures [61]. In addition, protective clothing against
chemical warfare, trapping aerosols, windproof and wound dressing products for
military purposes were other applications of functionalized textiles. At the onset of
next generation smart textiles, the functionalities of these textile grade fibers have
shifted focus towards smart fibers with the incorporation of wide panel of novel
nanoparticles, few to be mentioned are ZnO [20], TiO 2 [62], SiO 2 [63], Au [64],
Cu [65], nano-clay, Ag [66], polymers [67] and their composites. Owing to their
stability, inorganic materials are well preferred than organic materials.
2.5.1 Functionalities Incorporated
When placed in the bacterial environment, nanoparticles (especially Ag, which
exhibits anti-bacterial properties) infiltrate the bacterial cell resulting in cellular
leakage, which eventually leads to the death of that particular cell [68]. To block
the harmful UV rays, the choice of the nanoparticles should be such that its bandgap
matches with the incident photons. When the textile is modified by this layer, the
energy of the incident UV photons is absorbed, henceforth the penetration through
textile stands prevented. Cellulose as such, is hydrophilic and easily flammable.
But, when its surface is modified with nanoparticles, based on the morphology and
D. K. Subbiah et al.
confining those metals to nano scale offers much more conductivity (e.g. gold, silver).
In general, metals are defined as solid, hard and mechanically stable materials. In
transistor technology, especially in metal oxide semiconductor field effect transistor
(MOSFET), metals were used as the gate material. This was because the material
that was employed as the gate in the transistor must have high conductivity, with
the applied voltage between terminal (source) and metal (gate) regulates the channel
voltage. Metals are also found in liquid form (e.g. mercury, gallium), offering both
metallic and fluidic properties [54].
Moreover, metals provide appreciable deformable nature wherein it could retain
their function under stretching, bending and twisting action. Such attractive properties facilitate the fabrication of flexible electronic devices. Deploying such electronic
devices (e.g. sensor, antenna) interconnected by metal and deformable on a flexible
substrate like textile, plastic would pave a way to attain a benchmark in wearable
electronics.
2.5 Multifunctional Textiles
Textile is one of the basic commodities, which has been historically used for clothing
over centuries. In this techno-era, attempts have been made to make it smart for multitasking. Improvisation of traditional fabric in properties such as hydrophobicity [55]
(dirt-free), conductivity [56], antimicrobial activity [57], ultraviolet resistance [58],
flame retardancy [59] and stimuli-responsiveness have been reported so far. Modified
textile with super hydrophobicity results in self-cleaning [60] properties could be
used to separate oil-water mixtures [61]. In addition, protective clothing against
chemical warfare, trapping aerosols, windproof and wound dressing products for
military purposes were other applications of functionalized textiles. At the onset of
next generation smart textiles, the functionalities of these textile grade fibers have
shifted focus towards smart fibers with the incorporation of wide panel of novel
nanoparticles, few to be mentioned are ZnO [20], TiO 2 [62], SiO 2 [63], Au [64],
Cu [65], nano-clay, Ag [66], polymers [67] and their composites. Owing to their
stability, inorganic materials are well preferred than organic materials.
2.5.1 Functionalities Incorporated
When placed in the bacterial environment, nanoparticles (especially Ag, which
exhibits anti-bacterial properties) infiltrate the bacterial cell resulting in cellular
leakage, which eventually leads to the death of that particular cell [68]. To block
the harmful UV rays, the choice of the nanoparticles should be such that its bandgap
matches with the incident photons. When the textile is modified by this layer, the
energy of the incident UV photons is absorbed, henceforth the penetration through
textile stands prevented. Cellulose as such, is hydrophilic and easily flammable.
But, when its surface is modified with nanoparticles, based on the morphology and