Use of synthetic dyes for dyeing of textile fabrics are most problematic environmental concerned for textile industry owing to their toxic effect
on ecosystem. Thus, sustainable novel technologies for textile dyeing are needed that utilize enhanced dye uptake and improved performance
characteristics of fabric. Such technology may reduce dye concentration in waste-water effluents from textile sector and ultimately become energy
efficient and cost effective. Plasma technology has proven to impart enhanced dye exhaustion, dye penetration, dyeing in shorter time with minimal of
chemical auxiliaries and energy usage. The potential attributes of plasma on textile dyeing is discussed in this article..
Textile sector is facing an increased global competition
in current decade owing to changing market conditions. The
utilization of novel technical skills is thus forced for fabricating
textile products for high quality performances . This aspect is
further accelerated to employ such technologies due to high level
of hazardous chemicals in large quantities and volume of waste
water textile effluents. Thus extra purification methods are needed
to purify these effluents. As alternative to conventional chemical
treatments, radiation has potential to tailor surface characteristics
of polymeric, micro and nanostructures . Among all available
surface treatment methods, Plasma irradiation is observed a
remarkable significance. This is a green, dry, worker friendly and
ecofriendly method that can alter surface properties without major
change in bulk performance of textile materials. Owing to heat
sensitive nature of textile polymeric materials, non-thermal plasma
is particularly suitable [3,4].
Plasma treatment Vs chemical modification
Surface morphology of fiber greatly influences the choice of
processing method for it. For example, a fiber having scales on
its surface may exploit unwanted phenomenon like barrier of
diffusion or felting. Therefore, many fiber degradation effects as
well as environmental issues are concerned by using chemical
treatment for modification of such fibers [5,6]. Thus a number of
green processes have focused due to ecological and economical
awareness to deal these issues.
As comparison, low yield of dyeing and more than 50% dye lost
in waste water effluent, some esthetic and environmental issues can
minimized by plasma treatment before, during dyeing or finishing
processes. Advantageously, this technology can operate at ambient
conditions with lesser of no chemical auxiliaries are needed. Thus,
this technology is attributed green textile technology.
Various characteristics have developed for textiles e.g.,
high level of shrink resistance [7-10] wet ability [11,12]. Low
temperature plasma (LTP) treatment has shown significant plasmapolymer
surface interactions to tailor process and performance
characteristics of dyeing wool fiber including improved dye uptake,
lesser felting dispute, increased electro negativity on fiber surface
[7,13-16]. In this way, penetration of dye become more penetrated in
treated fiber and ultimately enhance coloration achieved. Exocutile
A-layer of wool fiber is expected to under gone cytokine oxidation
under exposure of sputtering results of plasma. Ultimately, partial
swelling of A-layer at fiber surface occurred owing to decrease in
cross-linkages and improved fiber-dye affinity. Comparatively,
Acetone/argon plasma is favored in place of helium/argon plasma
to improve dyeing ability of wool at room temperature towards acid
dyes . Furthermore, coupling enzymatic treatment along with
low temperature plasma pre-treatment is significant to further
increase dyeing rate of cotton and wool fabrics toward milling
acid dye . This performance achieved by simultaneous effect
of enzymatic and plasma treatments which attack in interior and
exterior of fiber respectively. Nature of plasma gas also contribute
its significant effect for modifying fiber surface. For example,
chrome dyeing of wool fabric is favored to use nitrogen plasma in
place of oxygen plasma . Thus, mordant treatment of wool fabric
in textile processing can be substituted with plasma sputtering
of which gives better performance characteristics of fabric and
enhanced antibacterial properties advantageously . Different
schematic view of plasma sputtering setup for fabric is depicted
in Figure 1. The performance of air plasma pre-treated fabrics is
dependent to optimized process parameters [20,21]. Unwanted
results may achieved at prolonged plasma exposure of fibe r such
as change in appearance of fabric and heavier weight loss.
Figure 1: Schematic view of (upper) corona plasma equipment used for acrylic fabric treatment  (lower) the DC magnetron sputtering setup .
Figure 2: SEM micrographs of acrylic fiber.
(b) After corona treatment for 7s
(c) 28s. Evidence of the effect of matter removal by plasma etching observed in (b) and (c) 
In place of natural fibers, plasma technology is shown
extraordinary results for synthetic fibers as well. PET fabric treated
by cold plasma exhibit enhanced dyeing performance owing to
enhanced surface area and surface roughness induced by plasma
treatment [22,23]. Enhanced dye exhaustion is also may be due to
greater affinity and enhanced water swelling ability of PET fiber
towards polar parts of dyes during dyeing process of treated PET
fabric . Anti-reflective coating of PET with better coloration is
achieved by plasma sputter etching of organo-silicon compounds
on surface of PET . Corona plasma is able to remove unwanted
matter substance from surface of acrylic  and polyamide 
fibers as depicted in Figure 2 & 3.
Figure 3: (a) untreated PA 66 fibers and (b) plasma-treated PA 66 fibers at 100W, 3min, 10L.min-1, and 1 Torr .
Furthermore, characteristic functional groups may develop on
surface of fiber by plasma technology along with specific carriers for
fabricating various functional and high performance applications.
As a result, hydrophilicity and capillarity achieved e.g., enhanced
dye diffusion in the amorphous region of PET/Viscose [28-30].
Plasma technology introduced oxidized anionic polar groups (i.e.,
C=O, COOH) on fiber surface with increased hydrophilicity which
enhances the interactions of fiber with dye [30,31]. The mechanism
of disperse dye with treated PET fabric surface is shown in Figure 4.
Figure 4: (a) The mechanism of disperse dye with treated PET fabric surface and SEM images (b) untreated after dyeing (c) treated after dyeing .
Another significant approach of utilization of Plasma technology
is aim at grafting of suitable functional group on surface of fiber
which also improves interaction of dye and fabric surface .
Introducing oxygen atoms onto surface of fabric by double barrier
discharge (DBD) plasma from atmospheric oxygen is another
example of this approach. Thus, plasma technology is a versatile
technique having a number of advantages over conventional
treatment methods. Plasma treatment has tested with a number of
natural and synthetic fabrics such as silk [33,34], wool [35-
41], cotton [16,42-51], polyethylene , polypropylene [53-55],
polyester [22,56-60], polyamide [61-64], ramie  and viscose
This article is an attempt to exploit and summarize potential
aspects of plasma technology for textile dyeing to be employed
in textile sector. Plasma treatment is a dry and clean technique
operates at ambient temperature which is able to improve
coloration and to develop characteristic functionalities on surface
of textile fabric without altering the performance of bulk fiber.
Furthermore, plasma treatment can couple with other natural
treatment methods which further improve the performance of
treated fabric. This results insignificant reduction of toxic chemicals
and auxiliaries in effluent load which diminish energy usage and
cost and environmental impact.
Professor, Chief Doctor, Director of Department of Pediatric Surgery, Associate Director of Department of Surgery, Doctoral Supervisor Tongji hospital, Tongji medical college, Huazhong University of Science and Technology