**6. Influence of plasma sputtering treatment on natural dyeing and antibacterial activity of wool fabrics**

In this paper, the effect of plasma sputtering treatment on the natural dyeing properties of wool and the possibility of substituting it for mordant treatment have been studied. Madder and weld as natural dyes and copper sulfate (CuSO4) as a metal mordant have been used. Also, copper as the electrode material, in a DC magnetron plasma sputtering device was used. The color strength of samples was analyzed using a reflective spectrophotometer and washing and light fastnesses were investigated according to I.S.O. standard recommendations. The results show that, the color strength and fastness of dyed wool

Effect of Plasma on Dyeability of Fabrics 343

into it at a pressure of 2×10-2 torr. Voltage was kept at 2000 V and the discharge current was 220 mA. The duration of Cu deposition was 3, 7 and 15 min for different samples. All samples were analyzed using EDX for comparing the amount of copper on the samples. As it is shown in Figure 13, the amount of copper on plasma sputtered samples is more than CuSO4 treated one which demonstrates that in a very short time of plasma sputtering, large amount of copper has covered the surface of the samples. Thus by increasing the time of

After dyeing the samples, the color intensity of them has been measured and compared using a reflective spectroscopy in the range of 400-700 nm. The results are shown in Figure 14 and 15. As it can be seen in Figure 14, the reflection factor for the mordanted sample by

sputtering, it is possible to increase the amount of copper sputtered on the samples.

Fig. 14. The Reflection factors of dyed samples with madder

Fig. 15. The reflection factor of dyed samples with weld

samples have been improved after plasma treatment. The antibacterial counting test was also used for determining the antibacterial efficiency of plasma treated and mordanted samples and the durability of antibacterial properties of them was compared. The scoured wool fabric was divided in 2 parts, one was mordanted by copper sulfate, and the other deposited by a plasma sputtering device. The chamber was evacuated to the pressure of 2×10-5 torr, using a rotary and also a diffusion pump, and then argon gas was introduced

Fig. 13. The EDX results of sputtered wool

samples have been improved after plasma treatment. The antibacterial counting test was also used for determining the antibacterial efficiency of plasma treated and mordanted samples and the durability of antibacterial properties of them was compared. The scoured wool fabric was divided in 2 parts, one was mordanted by copper sulfate, and the other deposited by a plasma sputtering device. The chamber was evacuated to the pressure of 2×10-5 torr, using a rotary and also a diffusion pump, and then argon gas was introduced

Fig. 13. The EDX results of sputtered wool

into it at a pressure of 2×10-2 torr. Voltage was kept at 2000 V and the discharge current was 220 mA. The duration of Cu deposition was 3, 7 and 15 min for different samples. All samples were analyzed using EDX for comparing the amount of copper on the samples. As it is shown in Figure 13, the amount of copper on plasma sputtered samples is more than CuSO4 treated one which demonstrates that in a very short time of plasma sputtering, large amount of copper has covered the surface of the samples. Thus by increasing the time of sputtering, it is possible to increase the amount of copper sputtered on the samples.

After dyeing the samples, the color intensity of them has been measured and compared using a reflective spectroscopy in the range of 400-700 nm. The results are shown in Figure 14 and 15. As it can be seen in Figure 14, the reflection factor for the mordanted sample by

Fig. 14. The Reflection factors of dyed samples with madder

Fig. 15. The reflection factor of dyed samples with weld

Effect of Plasma on Dyeability of Fabrics 345

the Cu sputtered dyed fabrics are improved and fastness in range between good to excellent has been achieved. As mentioned before, the wash and light fastness of natural dyes are not satisfactory, so many research are carried out for improving these fastnesses. Here it has shown that by using plasma sputtering technique we can dye wool samples by natural dyes easily with very good wash and light fastness. This technique may found many applications

CuSO4 treated madder dyed wool 4 5-6 3min-coated-madder dyed wool 4 5-6 7min-coated-madder dyed wool 4-5 7-8 15 min-coated-madder dyed wool 4-5 7-8 CuSO4 treated weld dyed wool 3-4 5 3min-coated-weld dyed wool 5 7-8 7min-coated-weld dyed wool 5 7-8 15min- coated-weld dyed wool 5 7-8

In another point of view, in recent years, the demand for antibacterial fabrics in domestic and abroad markets has grown significantly because of more awareness of the potential threat of spreading diseases. Bio-protective fabrics such as medical clothes, protective garments, and hygienic textiles are the main application of the antibacterial fibers (Schmidt-Przewozna et al. 2008). Natural textiles such as those made from cellulose and protein fibers are often considered to be more vulnerable to microbe attack than man-made fibers because of their hydrophilic porous structure and moisture transport characteristics. Thus, the use of antibacterial agents to prevent or retard the growth of bacteria is becoming a standard finishing for textile goods. However, conventional finishing techniques applied to textiles (dyeing, stain repellence, flame retardance, antibacterial treatments) generally use wetchemical process steps and produce a lot of wastewater. Plasma treatment, on the other hand, is a dry and eco-friendly technology, which offers an attractive alternative to add new functionalities such as water repellence, long-term hydrophilicity, mechanical, electrical and antibacterial properties as well as biocompatibility due to the nano-scaled modification on textiles and fiber. Moreover, the bulk properties as well as the touch of the textiles remain unaffected (Hegemann et al, 2007 ; Yuranova et al, 2003 ; Chen et al, 2008 ; Yu et al, 2003, Park et al, 2008 ; Ghoranneviss et al, 2007 ). In this paper in addition to investigation about the effect of plasma sputtering and mordant treatment on wool natural dyeing, the antibacterial efficiency of both plasma treated and mordanted samples have been also studied. The tests done to evaluate antibacterial textiles were divided into two types, agar based zone of inhibition tests and bacteria counting tests. The agar culture medium is transparent, when the bacterium is inhibited from growth, a transparent area in the form of a halo around the fabric will be observed. No halo for untreated wool fabrics has been observed. This control test shows that the original fabric does not have any antibacterial property, while the CusO4 treated and Cu-coated samples show very good antibacterial activity. The reason is that the interaction between copper ions and bacteria can change the metabolic activity of bacteria and eventually cause its death. The diameter of the halo is

**Samples Wash Fastness Light Fastness**

in carpet industry as well.

Table 3. The results of wash and light fastness

CuSO4 when dyed by madder is very close to the Cu-deposited samples with 3 minutes plasma treatment. However in Figure 15 which shows the case of dyeing with weld, the reflection factor of 7 min Cu-sputtered sample is close to the reflection factor of CuSO4 mordanted sample. The K/S values of the samples corresponding to the cases of Figures 14 and 15 are shown in Figures 16, 17 respectively. The Figures show that by choosing a proper condition for sputtering, it is possible to improve the natural dying properties of wool

Fig. 16. The K/S values for dyed samples with madder

Fig. 17. The K/S values for the dyed samples with weld

As we mentioned before, the durability of dyed wool fabrics has been also evaluated in terms of fastness towards washing and light, using the gray and blue scale according to ISO standard recommendations. The results are shown in Table 3. Assessment of fastness involves a visual determination of either change in shade or staining of an adjacent material and the graduation of the gray tones in the scales is defined as the smallest difference in depth, which is of commercial significance. As shown in Table 3, the fastness properties of

CuSO4 when dyed by madder is very close to the Cu-deposited samples with 3 minutes plasma treatment. However in Figure 15 which shows the case of dyeing with weld, the reflection factor of 7 min Cu-sputtered sample is close to the reflection factor of CuSO4 mordanted sample. The K/S values of the samples corresponding to the cases of Figures 14 and 15 are shown in Figures 16, 17 respectively. The Figures show that by choosing a proper condition for sputtering, it is possible to improve the natural dying properties of wool

Fig. 16. The K/S values for dyed samples with madder

Fig. 17. The K/S values for the dyed samples with weld

As we mentioned before, the durability of dyed wool fabrics has been also evaluated in terms of fastness towards washing and light, using the gray and blue scale according to ISO standard recommendations. The results are shown in Table 3. Assessment of fastness involves a visual determination of either change in shade or staining of an adjacent material and the graduation of the gray tones in the scales is defined as the smallest difference in depth, which is of commercial significance. As shown in Table 3, the fastness properties of the Cu sputtered dyed fabrics are improved and fastness in range between good to excellent has been achieved. As mentioned before, the wash and light fastness of natural dyes are not satisfactory, so many research are carried out for improving these fastnesses. Here it has shown that by using plasma sputtering technique we can dye wool samples by natural dyes easily with very good wash and light fastness. This technique may found many applications in carpet industry as well.


Table 3. The results of wash and light fastness

In another point of view, in recent years, the demand for antibacterial fabrics in domestic and abroad markets has grown significantly because of more awareness of the potential threat of spreading diseases. Bio-protective fabrics such as medical clothes, protective garments, and hygienic textiles are the main application of the antibacterial fibers (Schmidt-Przewozna et al. 2008). Natural textiles such as those made from cellulose and protein fibers are often considered to be more vulnerable to microbe attack than man-made fibers because of their hydrophilic porous structure and moisture transport characteristics. Thus, the use of antibacterial agents to prevent or retard the growth of bacteria is becoming a standard finishing for textile goods. However, conventional finishing techniques applied to textiles (dyeing, stain repellence, flame retardance, antibacterial treatments) generally use wetchemical process steps and produce a lot of wastewater. Plasma treatment, on the other hand, is a dry and eco-friendly technology, which offers an attractive alternative to add new functionalities such as water repellence, long-term hydrophilicity, mechanical, electrical and antibacterial properties as well as biocompatibility due to the nano-scaled modification on textiles and fiber. Moreover, the bulk properties as well as the touch of the textiles remain unaffected (Hegemann et al, 2007 ; Yuranova et al, 2003 ; Chen et al, 2008 ; Yu et al, 2003, Park et al, 2008 ; Ghoranneviss et al, 2007 ). In this paper in addition to investigation about the effect of plasma sputtering and mordant treatment on wool natural dyeing, the antibacterial efficiency of both plasma treated and mordanted samples have been also studied. The tests done to evaluate antibacterial textiles were divided into two types, agar based zone of inhibition tests and bacteria counting tests. The agar culture medium is transparent, when the bacterium is inhibited from growth, a transparent area in the form of a halo around the fabric will be observed. No halo for untreated wool fabrics has been observed. This control test shows that the original fabric does not have any antibacterial property, while the CusO4 treated and Cu-coated samples show very good antibacterial activity. The reason is that the interaction between copper ions and bacteria can change the metabolic activity of bacteria and eventually cause its death. The diameter of the halo is

Effect of Plasma on Dyeability of Fabrics 347

wool 99.4 99.4 4 mm 4 mm

sputtered wool 99.5 99.5 4 mm 4 mm

sputtered wool 99.5 99.5 4 mm 4 mm

sputtered wool 99.6 99.5 4 mm 4 mm

So by Cu-sputtering , not only the wool fabrics could be dyed easily in a short time without need to any wet medium , but also they could gain very good antibacterial properties. The results show that, the sputtering has improved the natural dying properties of wool fabrics. It has also improved the wool resistance to washing and light. The dyed treated samples

As has been demonstrated, plasma treatments of textiles look very promising. They can be used both in substitution of conventional processes and for the production of innovative textile materials with properties that cannot be achieved via wet processing. They are applicable, in principle, to all substrates, even to those that cannot be modified by conventional methods. In general, no significant alteration of bulk properties is produced. They are fast and extremely gentle, as well as environmentally friendly, being dry processes characterised by low consumption of chemicals and energy. When they cannot replace an existing wet process (dyeing and some finishing), if used as pre-treatments, they can reduce markedly the amount of chemicals required by the process and the concentration of

The great advances of the last decades in the field of the science of materials are now ready to enter into the field of textiles and it is already possible to envisage that, in the next ten years, the clothing–textile industry will undergo a dramatic revolution. Smart textiles, completely new fibres (nanofibres, etc.), and new textile applications in unexpected fields can be expected. Also, our way to consider clothing is going to change completely. Environmental aspects are going to play a more and more important role. Under these perspectives, plasma processes are certainly going to supersede many traditional finishing

Abdel-Hamid, H.M. (2005). Effect of electron beam irradiation on polypropylene films –

dielectric and FT-IR studies. *Solid-State Electronics,* volume 49, pp 1163–1167, ISSN:

Table 4. The antibacterial activity of the treated samples before dyeing

have also gained very good antibacterial properties (Shahidi et al, 2011).

Counting test (Reduction percentage of bacteria), E.coli

Inhibition zone, S.Aureus

Inhibition zone, E.coli

Counting test (Reduction percentage of bacteria), S.Aureus

Samples before dyeing

CuSO4 treated

3 min copper

7 min copper

15 min copper

**7. Conclusion** 

pollutants in the effluents.

processes.

**8. References** 

0038-1101

shown in Table 4. As it is shown, coating the samples by Copper has produced an antibacterial effect in it. Figure 18 illustrates the results of counting test for untreated wool sample. As it is seen, too many bacteria are spread over the plate. The results of treated samples are shown in Figure 19. As shown, coating the samples by copper for 7 minutes has significantly decreased the amount of survival bacteria colonies. Similar results were achieved for the rest of the coated samples. We should mention here that the amount of bacteria spread over the agar plate is also decreased for the CuSO4 treated samples. However these process which are done in a wet medium under a long duration, at least 60 minutes [Chen et al, 2008 ; Hong and Sun, 2008 ; Kumar et al, 2005 ; Chen & chiang, 2008], are not comparable with easily obtained treatment through plasma sputtering technique.

Fig. 18. The photo of bacteria spread over the plate in case of untreated wool

Fig. 19. The antibacterial activity of copper coated sample for 7 min.

shown in Table 4. As it is shown, coating the samples by Copper has produced an antibacterial effect in it. Figure 18 illustrates the results of counting test for untreated wool sample. As it is seen, too many bacteria are spread over the plate. The results of treated samples are shown in Figure 19. As shown, coating the samples by copper for 7 minutes has significantly decreased the amount of survival bacteria colonies. Similar results were achieved for the rest of the coated samples. We should mention here that the amount of bacteria spread over the agar plate is also decreased for the CuSO4 treated samples. However these process which are done in a wet medium under a long duration, at least 60 minutes [Chen et al, 2008 ; Hong and Sun, 2008 ; Kumar et al, 2005 ; Chen & chiang, 2008], are not comparable with easily obtained treatment through plasma sputtering technique.

Fig. 18. The photo of bacteria spread over the plate in case of untreated wool

Fig. 19. The antibacterial activity of copper coated sample for 7 min.


Table 4. The antibacterial activity of the treated samples before dyeing

So by Cu-sputtering , not only the wool fabrics could be dyed easily in a short time without need to any wet medium , but also they could gain very good antibacterial properties. The results show that, the sputtering has improved the natural dying properties of wool fabrics. It has also improved the wool resistance to washing and light. The dyed treated samples have also gained very good antibacterial properties (Shahidi et al, 2011).
