In recent years, interest in water or stain-resistant surfaces has increased. Preparation of water and stain-resistant or wet (super hydrophobic) fabric surfaces are important for many areas. Super hydrophobic properties can be achieved by covering the fabric surface with nano materials. Various materials are used for this purpose. One of the most effective ways to give a surface water or stain retention is to coat the surface using chemical solutions that will provide the desired feature.

 

The fact that solid materials have water and stain resistant properties is directly related to the surface characteristic. The chemical composition and geometric structure of the surface are important at this point. In addition, surface analysis is very important factors in order for the coatings made to be homogeneous and not to encounter a situation such as not coating at any point on the surface. For this purpose, contact angle analysis to the products obtained should be characterized by SEM (scanned electron microscopy), EDS (Energy Distribution X-ray 

 

Keywords: textile, water repulsion, oil repulsion, nanomaterial, contact angle

 

1. With the increase in science and technology and innovative products, the research we call smart textiles and the applications released as a result of these researches have ceased to be prototypes and are produced in today's industrial sectors and gradually started to gain a place in our daily lives with the end consumer, that is, to us (Güneşoğlu, 2009). Nanotechnological clothing, which includes wearable smart technologies and provides convenience in our daily lives, has turned into a giant sector that attracts attention not only in Turkey but also around the world and whose industry is growing day by day and has caused new horizons to be opened in the field of textile/clothing. These nanotechnological products, in other words, innovative products produced using production methods very different from traditional production techniques, are one of the contributions of modernized life to us (Çıracı et al., 2006).

 

Smart applications uncovered as a result of research on woven and knitted textile products can be applied in all processes starting from fiber, that is, raw material form, starting from the form, to finishing when examined in the mist obtained from literature research. The advantage of this is that there is no waste of time or adding processes for innovative product formation while the usual processes continue without the need for any extra processing. With the introduction of nanotechnology into our lives, the production techniques of smart products have shifted to very different points. Different materials (such as silver ions) are added to textile products, allowing them to clean themselves, as well as different designs can be created with the addition of apparatus such as electronic circuits and led lights.

 

In addition to the design difference, with the inclusion of 3D writings in our lives, production methods have changed; Using laser cutting techniques, many different kinds of designs and applications have become possible (Bozkaya, 2006).

 

When textile/clothing production methods are examined, one of the important points that is considered when innovating like other production techniques is to develop various methods to make their surfaces, that is, in other words, their appearance more beautiful, and to protect them from external influences while beautifying the exterior appearance and to increase the shelf life/consumption process. When these methods are examined, the oldest and most widely used technique is the painting process. While the paint coating process was used to change the outer surface images of textile products in the past, it was also aimed to decorate them and make them look different from each other with different colors, while it was also aimed to protect clothes or fabrics against external factors with the dyeing method. In order to ensure these effects, it is ensured that not only dyeing processes but also products with functional properties in production are produced using different production methods and materials.

 

When the properties of functional coatings are examined in general; In order to be used in the textile sector, it is important for the emergence of healthy structural products to be easy, cheap and most importantly environmentally friendly to apply. Nanotechnology, the most important production method where these features can be achieved and used in the garment/textile sector today, has recently taken its place in the sector in Turkey as well as in the world (Ilgaz, 2006).

 

When the nanoplating method was examined, it was determined that the materials to be coated were nanoscale (1-100 nanometers (nm) = 10-9 meters) and that there were production methods applied to the surface of the fabric using different methods, layer or regional coating techniques. Nano-size is the reason for preference When any physical or chemical process performed in the nano-size shown by new researches is examined, there are changes in macro dimension, that is, in other words, the processes that are visible in the visible size. For this reason, nano-sized coatings are included in production thanks to the different advantages they bring to the textile industry.

 

Since different approaches are formed in the society due to the development of technology, consumers expect different innovative products to be formed in the textile/clothing sector. They aim to make their lives even easier with these products. In recent years, interest in water and oil-repellent surfaces has been increasing by the consumer. The most effective way to give a surface a water and oil-repellent feature is one of the most important methods in production to cover the textile material, in other words, the fabric with water and oil-repellent material. As a result of the researches, when the history of this coating technique was examined, scientists returned to nature as in other sciences and applied the technique that exists in nature to fabrics with inspiration today and ensured the formation of this production method. Although muddy lakes and river beds grow in these regions when examined, the leaves of lotus, that is, lotus flower, are always clean, attracted the attention of researchers and caused them to carry out studies on this subject. As a result of the examinations, it was determined that the dust and dirt formed on the lotus flower leaves on the normal day were cleaned by water droplets formed as soon as it rained. When this cleaning technique is examined more deeply, it has been determined that the water droplets touching the lotus leaf flow only in droplets over the surface without soaking the surface of the leaf, and dust and dirt particles that attach to the drop surface by electrostatic method are easily removed from the surface with this technique. The most important part of this cleaning process, which water droplets pretend to sweep the surface, is determined that when the surface is examined, it is due to the fact that the surface is super hydrophobic, that is, the surface that does not like water (Özdoğan, Demir ve Seventekin, 2006).

 

The wetness of solid materials is basically a property related to surface chemistry. When the lotus flower leaves are examined, it is determined that the composition and geometric structure of the surface chemistry differs from other types; There are protrusions on the surface in micro dimensions and when their nano-dimensional examinations are made, they are covered with hydrophobic material on the surface. In another study, they determined that as a result of examining the wings of the desert beetle, which carry out its vital activities in the desert, it survived by tending to hold/hold water droplets in this way, with micro and nano-sized hydrophobic and hydrophilic regions on the wings. In other words, even protrusions and indentations formed on the surface can be effective in changing the chemistry of this surface and gaining hydrophobic or hydrophilic properties. In addition, another most important reason why surface chemistry has these properties is surface energy. Since the low or high energy of a solid surface will be effective in creating weak or strong bonds between it and the material on its surface, it is an event related to whether events such as surface adhesion occur or not as a result of these interactions.

 

Image 1. Water and stain resistant ready-made clothing produced with nanotechnology

 

The results of scientific research and studies carried out in recent years on the development of superhydrophobic, that is, in other words, surfaces that do not retain water and oil and prevent stain formation, show promise for the textile/clothing sector in the industrial field. The fact that the products provided by coating technology and produced using nano technology are products that clean themselves, stain-resistant and offer anti-microbial properties has been a development that can be a touchstone in terms of providing different alternatives to the consumer and providing innovative products.

 

When the products developed with the latest technology are examined, the attention of the public is attracted by the fact that the first people to experience these innovative products are artists and many famous names show such products in television, newspapers and other media publications, and it is not difficult for the product to become usable in daily life thanks to the advertisement of the product made. The usage areas of super hydrophobic surfaces or production techniques are not only artistically, but also have led to clothing/fabric use opportunities in many different ways in many areas such as water-repellent tent cloths, workwear and umbrellas and their usage areas to increase. This feature, which is especially used in clothes designed for medical purposes, is used by the personnel during surgeries where surgical interventions are performed due to its super hydrophobic and antibacterial properties, facilitating sterilization and cleaning after the procedure (Xu et al., 2010).

 

2. NANOTECHNOLOGY AND TEXTILE APPLICATIONS

 

The word nano is a kelen word for ‘dwarf’ in Greek and is now used as a fore jewelry in the unit of physical measurement. Using the nano prefix, different unit measurement values, such as time, volume and length... etc., an expression is obtained that gives a smaller meaning of one billion than this unit of measurement. (Security, 2007: 27)

 

Nanotechnology is accepted as an engineering field by renewing the structures of molecules at the atomic level and creating a brand new molecule and revealing materials. Changing the chemical and physical structures and building blocks of matter on the nanometer scale is the creation of more optional systems by combining more functional materials than before. In other words, the process of processing, modifying the structures of atoms at the molecular level and gaining brand new features is called nanotechnology. (Gülşenoğlu, 2005: 224-230) 

 

When nanoparticles, which are the main structural unit of nanotechnology, are examined, a particle with a small one billionth of a meter is mentioned that cannot be perceived by the living eye; for this reason, many analysis methods have been developed to discover and examine these structural units in materials. As a result of these structures being so small, behavior such as the materials around them cannot be expected. For this reason, when the chemical, physical and biological activities of these structures are examined, the general laws to which today's materials comply are invalid. (Vural, 2003:186-187)

 

Nanotechnology is constantly attracting the attention of scientists as a new technology. For this reason, research on this subject is ongoing and many studies are carried out. It is aimed to complete the development process by 2025 by continuing such studies for the next 10 years. It is stated that this new technology, which has completed the development process, will bring brand new innovative products and production technologies. In the development process, it is thought that the market share of nanotechnological applications will be $3 trillion and it is observed that there will be an increase in continuous market share. This subject is supported as the required field for priority research in many countries and universities. (Mr., 2006:1) 

 

It is obvious that the advantages created by the nanotechnology revolution will be the methods and materials used most effectively by humanity in the near future. It seems that nanotechnology will be a development that plays a very important role in the modernization and industrialization revolution in the next three decades, and the development levels of countries' use of nanotechnological methods will have a significant share in their level of development. For this reason, countries with this technology and have come a long way in terms of viability will increase the level of development, while other countries will lag behind. These studies are important not only in terms of academic and scientific studies, but also in terms of inclusion in production in terms of industrial and industrialization. (Özenbaş, 2006:2)

 

In the periods that started with the industrialization and modernization period at the beginning of the 19th century and the textile/clothing sector gained momentum, the use of products at the nanotechnological level was not so common. It was aimed to change them by adding additives to the products only in order to give different dimensions. However, with the participation of nanotechnology in our lives and the transfer of developments in the textile industry to practice, The addition of many different nanoparticles such as silver ions to the yarn and the creation of methods to prevent germ containment and odor have been a great revolution. It is not even a job to break new ground in the textile/clothing sector with the addition of features such as easy ironing or even needing washing, such as obtaining fabrics that remove water and oil, in other words, stain from the environment by using nano-coating methods, and adding features such as the advantages of non-polluted clothes. Transferring such features to fabrics and using nanotechnological methods are methods that are applied in many factories today and benefit the consumer and attract constant attention. In the near future, many scientific and industrial studies are carried out to obtain and produce products that can produce energy from clothes or textile products obtained from fabrics produced by nanotechnological methods, see and feel our body temperature and health conditions and even command our home system and other personal belongings. By providing optical and electronic properties to fabric yarns using different production techniques, products such as clothing with lighting properties, color-changing textiles and even invisibility capes can be obtained. (Mr., 2005:11)

 

The most important feature of textile products is that by changing the weaving and yarn properties, products with much different chemical and physical properties can be obtained from the fabric product normally with the surface treatments to be applied. These textile varieties are defined as ‘smart textiles’. By using smart textile types, it is ensured that products that provide thermal insulation and do not have pollution retention properties by using different methods than today's technology and applying superficial processes. Apart from this, as mentioned above, the work of clothes that can change color is carried out in universities. (Tamerler, 2008)

 

Since textile or clothing products are used in many areas today, multifunctional fabrics should be produced with smart technology and high performance products should be produced and used in priority areas (such as military and health). (Yılgör, 2006: 42)

 

When it comes to smart textile products; We think of products that can make our lives easier at many different points. The main ones are;

 

• Camouflage clothing that can be used in military areas and can detect environmental changes and provide color change.

 

• Clothes that can provide change due to seasonal change.

 

• Antibacterial clothing that kills germs.

 

• Clothes that can nourish the skin and massage the skin at the same time.

 

It is foreseen in the future that very functional, smart textiles will provide many advantages and make our lives easier with the inclusion of our daily lives (Bulat and Şener, 2009).

 

In Turkey, Vizyon 2023 Textile panel was held, giving importance to the development of original design, quality, efficiency, marketing and innovative ideas in the textile or clothing sector and the necessity of providing support was emphasized. It has come to the fore not only fashion, but also to encourage students and academicians to make progress in order to ensure technological developments in textile products and to carry out these scientific research, and even to implement and determine the support on these issues by our government. (www.vizyon2023.tubitak.gov.tr)

 

Smart clothes, which continue the development process today, have become commercialized by leaving academic fields of study and have been included in the market on the way to branding. Such garments and fabrics, which can be used in many sectors from the military field to the industrial field, have also started to be used significantly in the field of sports in the last decade. Some sports athletes played an important role in the production of smart textile products that are suitable for climate change, do not sweat-repellent and have antibacterial properties (Jose, 2005). So much so that using today's technology, the clothes of athletes and football players preparing for the Olympics are produced with unique features and innovative features containing fabrics suitable for their sports branches and delivered to the athletes. It is seen that new innovative products with many personalized features are produced not only in the military but also in the industrial field for protection and in other areas and will be widely used in the future. (Balcı, 2009)

 

Photo here 

 

Image 2. Smart clothes specially produced for athletes

 

It is estimated that the usage areas of the products to be produced in the future textile/clothing sector using nanotechnology can be shaped as follows;

 

• Long-lasting clothing where energy storage is possible,

 

• Clothes where information can be transmitted and obtained,

 

• Clothes that can vary in pores and thickness,

 

• Clothes that can facilitate the passage of drugs from the skin to the body in the medical field and can be used in these areas,

 

• Clothes that expose the crime

 

• Clothes that can provide safety and protection

 

• Self-breathing clothing,

 

• Clothes that allow wounds to heal,

 

• Clothes that can resist gravity, comply with atmospheric conditions or allow swimming underwater,

 

When the Turkish textile and clothing sector is examined, the main companies producing smart textiles can be listed as follows; Anteks, Yeşim Tekstil, Karsu Tekstil, Sude Suni Deri San. Inc.. (Laminatech), Abbate, Orka Group, İstanbul Çorap, Yeğin Group, Has Tekstil, Dema Tekstil, Fiberflon, Altınbaşak Tekstil, Zorlu Tekstil, Hakkoymaz Tekstil...etc. are textile companies.

 

Has Tekstil San. ve Tic. Ltd. Şti. As a result of the literature researches carried out when the products were examined, it was included in the Turkish market with the Clothas brand for the first time in 2004 by producing water and stain-resistant products, and together with the pants it produced under this brand name, they also offered products to consumers that do not hold odor, comply with climate change, relieve stress and can And by continuing its investments in accordance with these developments, it continues to make a name for itself as one of the many companies that produce smart textiles today. (www.tumgazeteler.com)

 

Yeşim Tekstil (Bursa company) acts as a locomotive in the sector by adding many different features such as water and stain-resistant properties as fast drying and easy ironing in the fabrics it produces by applying nanotechnological production techniques. With the use of fabrics provided by this company, they contribute to the production of many products that will facilitate the life of the final consumer by transforming nanotechnological smart fabrics into textiles or clothing in many fields. In addition, this company broke new ground and contributed to the development not only in fabric production but also in the field of weaving by using innovative designs in knitting technologies.

 

Orka Group (Istanbul company) impresses its new collection in the winter season. In addition to the fact that the clothes used/produced in this collection are water and or stain resistant, they also have the feature of providing moisture balance suitable for climate change; The fact that it includes smart technologies that prevent sweating and remove odors has caused this company to be more effective and preferred in the market. (www.hürriyetim.com)

 

The furniture produced by the Kelebek furniture group using oil and dirt-repellent, long-lasting, dry cleaning and washing resistant fabrics are good examples of nanotechnological production applications in the furniture sector other than the clothing sector. In addition, furniture produced from high wear resistant fabrics with the ‘bionic fabric’ series presented and promoted by Yeni Pazar won the appreciation and appreciation of the end user. (www.mobilyaonline.net)

 

As a result of long research and development studies, TAF has introduced uniforms produced by nanotechnological methods; antibacterial, water resistant, high strength, preventing sweat and odor by removing moisture; oil and stain resistant, produced in colors and patterns compatible with the color of the geographical structure in Turkey. (www.gazetevatan.com.tr)

 

Although the idea of the products produced using nanotechnology can be used in the field of textiles/clothing and their development is new, the rate in market share is very high today. As the usage area of this technology, which is important both economically and socio-culturally, becomes widespread and its importance in Turkey, its application and usage areas will increase and export opportunities to the world will change. In addition, since smart textiles, which will break new ground in terms of end-user consumers, will positively affect our daily lives, it is planned for companies in our country to realize their production in this field, as there will be a strong demand expectation in the coming years. Thus, the number of companies that include innovative technologies in their production using nanotechnology will increase.

 

3. SURFACE COATING TECHNOLOGIESS

 

The textile industry has made great progress, especially in the last decade, thanks to parts produced with some feature textile and fabric innovations. Expected innovations have been achieved especially in the textile and fabric sector with the help of technologies synthesized using different methods rather than traditional methods. Some of them; stain retention, antibacterial, adapting to the conditions of the environment in terms of climate and color... etc. (Wei, 2009; Yu et al., 2005). With the discovery and inclusion of new methods such as surface coating in the application, it has recently become easier to provide the desired properties to fabrics and other materials. (Davis et al., 2011; Ghoranneviss and Shahidi, 2014; Blood et al., 2013; Li et al., 1997). The application technique with the coating method on the surface of textile products with the left gel method encountered recently also plays an important role in creating more innovative products by using new technology by providing different perspectives to many companies in this sector.

 

It is known that nanotechnology applications are a very important and commercial development tool for the textile industry and thanks to numerous applications as a result of the developments in the past years. Since the majority of these developments occur in line with customer demands, these developments can be achieved using different methods in many areas. Since the textile sector adapted to the science of nanotechnology directly within its own structure, it has caused the most progress in this sector. First of all, although the nanotechnological applications applied are like disadvantages, today application methods have been changed and made more useful by making them more efficient. Nanomaterials, which did not have a permanent effect on fabrics in the first applications, could lose their functions after washing or clothing. However, thanks to the increasing surface application technologies with the developing technology, it has been ensured that high efficiency and functional products are produced by using properties such as surface/volume ratios and surface energies of fabric or textile materials.

 

In recent years, nanotechnology has shown that the fibers and yarns of fabrics or textile products meet the wishes of the sector and improve their characteristics by ensuring that they are softness, robustness, water repulsion, fireproof, airy and antibacterial properties.

 

In the 1990s, as a result of the examination of the microstructures of the lotus flower (lifer flower), which has a water-repellent feature, plant leaves, it was determined to have hydrophobic properties, and when these structures were imitated and applied to textile products, textile products with water repellent properties were obtained. These textile products with super hydrophobic properties have been used since then and a wide variety of studies have been carried out on this subject by using different analysis methods with the help of technological developments in order to determine this feature (Ağırgan et al., 2009).

 

If the hydrophobic surface tends to stop globally, not the tendency of the water drop to get wet or comes to the surface, it is called the hydrophobic surface, which means ‘hydro’ water and ‘phobos’ fear. In other words, the hydrophobic surface has the meaning that does not like water in terms of surface properties. Using the contact angle method, the soakability and degree of a fabric or surface by any liquid can be determined. While the contact angle is less than 900 indicates that the surface is wettable (hydrophilic), in cases where it is large, the surface is defined as a wet (hydrophobic) surface. If the contact angle is above 1500 or approaching 1800, these types of surfaces are defined as superhydrophobic surfaces.

 

The most important feature in increasing stain resistance such as water and oil in textile products, in other words, is to prevent the textile or fabric from getting wet with liquid. When the basic principles of surface interactions between liquid-contact fabric structures are examined, theoretically, the fact that these surface properties can be easily changed with the micro and nano-sized surface changes on the surface of the fabric are encountered, and these studies were explained by Schrauth.

 

Figure 1.2.1. Hydrophilic, Hydrophobic Surfaces (Özdoğan, Demir, Seventekin, 2006:288)

 

The criterion of wetness of solid surfaces such as fabrics and textiles is mainly directly proportional to the chemical structure on the surface. It is directly related to the composition of the surface, that is, what substances it consists of, surface energy and the geometric structure of this surface (Cerne et al., 2007). When the leaves of the lotus flower were examined, it was observed that micron and nano-sized protrusions formed on the leaves and that the whole leaf were covered with these structures. Similarly, when the wing structures of the desert beetle are examined, it was examined that there are micro and nanostructures on the surfaces and that these structures have the ability to not hold water and dirt. When the wings are examined with the help of electron microscope, the water accumulated in hydrophilic regions with both hydrophilic and hydrophobic structures arranged side by side and in the hydrophilic regions as the basic structure tends to flow to the mouth of the insect in drops when it comes to the hydrophobic regions, and thus the insect meets the water needs by drinking this water droplet. In other words, when the study carried out here is examined, the protrusions and roughness on the wing surfaces increase the hydrophobic feature of the structure. Another feature is to increase the hydrophobic feature by increasing the energy of the surface. The high-energy structure of the surface ensures that liquids such as water or other similar oil on the surface lose their wettable properties and do not stain. This is due to the fact that weak bonds form between the liquids falling on the surface and the surface and thus tend to flow without interacting.

 

When the studies carried out for applications to provide water repellency properties of textile fabrics are examined, many methods were encountered in the literature. The main ones; Studies such as giving water repulsive properties as a result of applying silica gel nanoparticle, perfluoro oxylate-containing super hydrophobic mixtures and fluorine-free durable nano silane mixtures to cotton fabrics by surface coating method take up more space. In addition, there are many studies on giving water-repellent properties to fabrics as a result of applying silver and silica nanoparticles to the surface by impregnation method and thus giving woven fabrics ultra-hydrophobic properties (Vansant et al., 1995).

 

Innovations made to raise their properties such as strength, thermal resistance and strengthening effective intramolecule bonds to provide resistance to fabrics in the dry cleaning process to a higher level are also provided by strengthening polarity and hydrogen bonds in this context. In addition to increasing these properties, thanks to these feature development technologies applied to outerwear by strengthening polarity and hydrogen bonds, it helps textile products to be more resistant in climatic conditions such as snow and rain and to improve water repulsion properties and to improve their properties such as not getting wet easily with water and thus creating an air conditioning effect and thus being suitable for climatic In this method, as a result of impregnating hydrophobic groups on the outer surface of the fabric, that is, covering the surface with chemical methods, the feature is formed on the surface of the fabric by allowing areas with repellent but low surface energy. In addition, as a result of the surface coating of these materials, not only water, but also the chemicals used in the dry cleaning process are easily removed from the surface and damage to the fabric or textile is prevented. In order to make this feature continuous and not to be affected by any external factors or chemical processes, it is necessary to create a covalent bond between these substances and fabric surfaces. It is important that the bond formed between fibers and chemicals is strong or stable in terms of making them more efficient and permanent. Because textiles or fabrics are materials that can deform quickly and are exposed to chemical stages such as constant washing and dry cleaning.

 

Super hydrophobic surface research and scientific studies have been continuing for the last decade in terms of its use in industrial and engineering applications. Especially as a result of technological developments and the blending of chemical processes with advanced technology, at the point of meeting consumer demand with the development of the coating method used in the textile production process; self-cleaning, water and stain resistant, anti-microbial...etc. The production of fabrics or textile products has reached a very easy feasibility level (Shao et al., 2004). In order to obtain these properties, surface treatments such as physical vapor deposition and chemical vapor deposition must be applied. By coating the silica chemical substance used in the chemical vapor deposition method in nano size on the surface, metal oxide rods were created on the surface, thus, as mentioned above, super hydrophobic surfaces were created and wetting properties were changed by increasing the surface energy and roughness.

 

Nano surface coating processes are possible to be applied in two different ways;

 

• Physical Vapor Deposition (PVD)

 

• Chemical Vapor Deposition (CVD)

 

In addition to these methods, electrochemical methods (electrolysis) and chemically left-gel methods are also available; It is included in the literature as surface coating processes used to ensure that the surface structure of the fabric or textile material is suitable for the desired feature by applying to the surface.

 

İ. Physical Vapor Deposition (PVD)

 

The physical vapor deposition method, which has been applied for the last decade, is a method that depends on which chemical solids the surface to be coated with. In this method, the substance to be coated on the surface is atomized under a high vacuum and completed by coating the surface after the evaporation process. Since the most important factor affecting the efficiency of this method is high vacuum, it has been updated with technical equipment that has developed due to technological developments. Since any substance is prevented from infecting the fabric surface in the method developed with the development of vacuum technology, no degenerated zone is formed on the surface, so the hydrophobic or hydrophilic desired surface type maintains its continuity on the same axis (Mattox, 2010).

 

The other most important factor in the development of physical vapor accumulation technique is technological developments in the plasma system. PVD technique has developed with the development of plasma-supported, that is, ion coating (reactive chemical coating) method. Although this method is the most used method today, it is known for its high cost. But on the other hand, using this method, fabrics and textiles show high adhesion properties compared to other methods, even at low coating temperature values. In addition, homogeneous coating can be easier to provide and allows hard or soft coatings to be made as desired.

 

The most important advantage of the PVD coating system is that it is a cleaner and environmentally friendly coating method than other systems. It also does not require extra waste or cleaning, as it does not require chemicals like other techniques. In addition, the PVD method can be made using any desired inorganic chemical substance, that is, in other words, there are no chemicals that limit the PVD method. But on the other hand, this technique has two disadvantages; the most important of which is that the technique requires complex devices and, as a result, it is an expensive system. In addition, it is the most important factor that this system is a difficult production technique arising from the complex structure of the system during the process process, that is, that is, during the production phase. As a result of this factor; The user who will use the system must be an expert, and since the process is too long, it causes the production process to be prolonged. On the other hand, in this process, the strength and stability of the surface are increased very significantly.

 

Figure 1.2.1. (a) Surface coated by PVD method (b) Experimental PVD coating device

 

İi. Chemical Vapor Deposition (CVD)

 

In the chemical vapor deposition method (CVD), it is realized by coating the chemicals from one or more gas phases in the reactor under low pressure on the surface. CVD method is a chemical coating method and is a method performed by applying a certain solid material at a certain temperature level in one or more gas mixtures by providing optimum conditions. While a homogeneous thin coating surface is expected to be formed in the PVD method, on the contrary, a very dense pure but fine-grained coating surface is expected to be formed in this method. In this method, where high deposition speeds are achieved, deposition speed and application temperature are among the most important factor process parameters. Different values to be made especially in these parameters may cause the fabric or textile surface to be heterogeneous. In addition, when combined with plasma coating support to be added to this method, fragmented shapes of different structures can be produced (Park and Sudarshan, 2001).

 

Figure 1.2.1. Surface coated by CVD method and hydrophobic surface sample

 

İii. Electrolysis

 

As it is known, the electrolysis process is a coating method of a chemical mixture containing an ion solution by immersing two electrodes and giving current to these electrodes. It is the process of coating the substrates placed in the cathode section with metal charges as a result of the electrolysis process. In this process, the material to be coated is placed in the cathode section, while the material to be coated is placed in the anode section. When this process takes place and current is given to the container called ‘cell’, the coating process is carried out by taking ions from the material anode region in the cathode region (Yalçın, 1999).

 

İv. Sol-Gel Technology

When left-gel technology is examined, it is the most widely used chemical process in which high purity materials such as powder, thin film coating, fiber structures are produced. Since the sol-gel method is used in very different applications, it has been used as an interesting production method for science researchers and textile sector managers for the last decade.

 

The origin of the sol-gel chemical coating method is known as the method developed by Ebelman in 1845 to create a solid material by slow hydrolysis of salicylic acid esters. Later, this method was developed by Geffchen and developed and approved for the accumulation of oxide films on glass surfaces. The Sol-Gel method was used in the 1970s, becoming popular in the ceramics industry, and this method was developed and used to produce inorganic glass. Sol-gel chemical coating technique is one of the traditional methods applied as wet chemical processes, especially on surfaces where inorganic materials are desired to be coated (Goldschmidt and Streitberger, 2003).

 

Figure 1.2.4.1. Sol-Gel surface coating method

 

There are many advantages in this technique compared to other techniques; While this technique provides the opportunity to work at low temperatures, the concentration of molecules can also be kept under control. In addition, porosity control can be provided for the creation of high-energy surfaces in materials in this method. The homogeneity and surface structure of the material formed as a result of the process can be controlled at an atomic level. In addition, the process of coating geometrically constructed fabrics and textile products, which provide different properties with high purity and complex structure using the left-gel method, is carried out easily (Schindler and Hauser, 2004).

 

Figure 1.2.4.2. Characteristics of the fabric coated using the sol-gel method

 

1. Sol Gel Coating Techniques

 

1. Spin Coating method: In this method, it is dripped into the chemical center that needs to be covered on a coaster and then includes the method of coating the desired fabric with this chemical material with the effect of centrifugal force as a result of rotating it at high speed. In this method, the fabric surfaces are covered with a thin layer of film. While the chemical in the center is removed from the central region with centrifugal force, on the other hand, homogeneous thin film formation has been ensured thanks to this force. Then the fabric or textile material is dried and removed from the excess solvent environment and the coating process is completed by gelling by drying the last chemical on the fabric (Aegerter and Menning, 2004).

 

2. Dip Coating method: It is the oldest and traditional coating technique and the cheapest method compared to other techniques. Therefore, it is very preferred. In this method, the fabric is fixed to a carrier and it is dipped in the left prepared at the determined speed and covered in the form of a film by removing method. There are two important stages in the coating technique; one is the immersion speed and the other is the time kept in immersion. When these two factors are examined; immersion rate and immersion time (waiting time in the prepared solution) affect the homogeneity of the area to be covered on the fabric or textile and the coating thickness.

 

Figure 1.2.4.1. Coating method using immersion technique

 

3. Spray Coating method: In this method, it is ensured that the solution of the chemical or solid to be coated is prepared and then sprayed from the apparatus called nozzles in a pressurized manner and the fabric or textile product is coated by atomization method. The chemical solution to be sprayed or expected may be in a hot or cold environment, which varies entirely depending on the activity of the chemical solution and the coating method. If the solution is hot activated and its coating is efficient, the process is completed by applying the spraying process when the optimum value is provided by giving the temperature. It comes on the surface to be coated with high reactivity and forms continuous film. Then, with the evaporation of the solvent in the solution, only the desired substance-coated film formation is observed on the surface by coating the solid substance in the solution. With this method, nano and micron films are formed on the surface of fabrics or textiles of the substances formed as a result of the atomization of the chemicals in the solution are provided.

 

4. Flow Coating method: When this coating method is examined, the material to be coated is kept suspended in the form of a piece in this container by finding a place or container where the flow will occur and poured on the coating solution in the bottom. In this method, it is ensured that a film is created by pouring on the fabric or textile product that is desired to be coated, and the excess parts are collected in a warehouse at the bottom and the excess is deposited and stored for reuse for other processes. The most important factor here is that the coating thickness is homogeneous. For this, the shedding speed of the coating, the slope of the pad, the density of the coating liquid and the evaporation rate of the solvent in the solution are important.

 

B. Super hydrophobic Surfaces

 

Some of the chemical materials used to create superhydrophobic surfaces; polymers, silicones and metal oxides can be given as examples.

 

The development of superhydrophobic surfaces is an important step for the transition to the next stages in the textile sector with the development of nanotechnology and the application of new technology to these methods, in other words, a touchstone.

 

In textile engineering, the process of changing the properties of coatings and fabrics applied to the fabric surface with various chemical and physical methods using nanotechnology is called ‘finishment’, also called finishing. For this reason, the methods applied to the fabric surface and mentioned above can be called the finishing process. This definition, which is used especially for the process of giving hydrophobic properties to the fabric; It may cause effects on some fabrics. The reason for this is that in the method that can be given hydrophobic properties, fabrics are based on changing the surface energy with perfluoroalkyl groups. But the main disadvantage of this chemical material; it is bioreduced. For this reason, while the fabric coated with this material acquires hydrophobic properties; It also has the bioreduced property, which is the most important disadvantage of the material. For this reason, newly conducted scientific research is that this disadvantage will not occur and accordingly, surface coatings without perfluoroalkyl groups are made, and studies focus in this direction (Li et al., 2008).

 

When the literature researches are examined; It has been determined that metal oxides are effective in the creation of hydrophobic surfaces and are more suitable for creating disadvantages in terms of other methods. When metal oxide samples are examined; It is ensured that superhydrophobic surfaces are created by coating molecules such as zinc oxide (ZnO), titanium dioxide (TiO2), silver oxide (Ag2O) on the structure, in other words, on the surface (Yi et al., 2010). Here, zinc oxide (ZnO); It is more advantageous than other chemicals in improving photocatalytic properties, electrical conductivity properties and UV absorption properties. In addition, since this molecule is chemically and biologically reliable, it is very reliable for the living body. In addition, the low cost of these materials is very important for the availability of this method Xu et al., 2009).

 

İ. Chemical Processes Applied in Textile Products

 

It is defined as applying chemical finishing and using chemicals used for this process in order to ensure that textile products such as fabrics are required to have the desired feature. When the finished fabrics and textile products are examined, it will be seen that there are structural changes on the surface with other products that have not been finished and that there are different features in terms of elemental analysis.

 

The textile market includes many different departments and corresponds to many different sections. Some of these departments are; clothing, home textiles and technical textiles (fields such as medicine, factories). In these units, it is important that fabrics and or textile products do not retain water, oil and stains. While water retention, in other words, wetability properties are provided by the above-mentioned methods, oil retention feature can only be developed and achieved by using polymeric groups containing fluorocarbons. For this reason, the finishes applied to the surfaces of the fabrics; They can be modified for different properties depending on consumer demand and sector needs, and this change is applied to the methods described above, allowing chemical bits to change the surface structure. 

 

The most traditional chemical finishing; It is a water repulsion finish, that is, its finish. This ending has many uses in different sectors. Sometimes this purpose is a self-cleaning textile product, sometimes it can be used for fabrics or military materials that do not get wet in the rain. The only important purpose of the water repellency finish is to spread the surface of the fabric or textile and the fabric does not get wet. Apart from having these two features, the water repellent finish demands different advantages; the absence of static electricity formation, removal of stains by washing, the surface of the fabric is not rough, there is no discoloration during washing, there is no flammability feature...etc. The creation of water repellent finishing are some of the most important features of the water repell Of course; In line with customer demands, it should be easily ironed, easily folded, resistant to chemicals in processes such as dry cleaning...etc. At this stage, scientists make technological developments available in the textile sector to develop these problems. This is why the newly developed nanotechnology is examined and applied by textile engineers in this process and even reduces it to the processes that can be applied in the sector.

 

The most important feature of the water repellency mechanism is that the applied surface has low free energy regardless of the type of fabric, fiber, rope or textile product. When the opposite of this situation is examined, if the interaction between the water drops on the fabric and the fabric is examined, the surface tensions and interactions and even the molecular adhesion interactions in the liquid remain small, it maintains its structure in the form of drops. When contact angle measurement and other analyzes were made, it was determined that its angle was more than 1500. The drop does not spread at this stage and the fabric does not get wet.

 

For its repulsive property, critical surface energies, that is, surface tension (gc), must be less than the surface tension (gL cohesion force) of the liquid on the surface. The cohesion force value of water is known as 73 mNm-1, which ranges from 20 to 30 mNm-1 for oils. When these values are examined, it is seen that the surface tension of the water is 2 or 3 times higher than oil. When the literature research conducted here is examined, the fluorocarbon method applied for oil finishing is really very efficient for these applications. In addition, the surface tension of these chemicals is lower than the surface tension of water and therefore provides water retention, in other words, the finish created using fluorocarbon chemicals is used in fabrics and textile products as a positive development for both water and oil. However, as a result of coating the surface with fluorine-free chemicals, for example, as silicone coating (gc = 24-30 mNm-1), the ends created may not give the fabrics oil finishing properties while giving water-repellent properties. These endings also provide dirt and stain resistant properties. While it becomes easier to remove stains and dirt chemically from surfaces created in this way; Since there is no strong interaction/bond mechanically, it allows it to be easily removed with these processes.

 

There are many methods of giving textiles repulsive properties; 

1. PARAFFIN BASED PUSHERS

 

The oldest method in which water repellency property is used and formed in fabrics and textiles is production techniques using paraffin-based chemicals. While water repellency is provided at the optimum level in these techniques; oil repulsion cannot be achieved. This emulsion contains aluminum or zirconium salts of fatty acids. These chemicals establish polar-apolar ion balance in the fabrics and help the finish to form a strong bond by allowing the fleece fabric surface and between the fiber to enter and stick more easily. As a result of coating fatty acids containing polar tip parts with metal salts as a result of their interaction with the prepared emulsion solutions, paraffinic solution and hydrophobic parts come together and cause low-cost and homogeneous surfaces with high water repulsion. However, since the chemical stability of these solutions is very low, they are not resistant and cannot be permanent in processes such as dry cleaning and processes involving chemical abrasives such as washing. In addition, since the vapor permeability of paraffins is high in terms of their chemical structure, their use for water repellency is limited.

 

2. STEARIC ACID-MELAMINE BASED PUSHERS

 

When the chemical compounds formed as a result of the reaction of stearic acid and formaldehyde melamine chemical compounds were examined, it was seen that these emulsion solutions were water-repellent solutions and helped to give fabrics or textile products the desired properties. As a result of interacting with each other and also with cellulolysis structures by forming chemical cross-links, the N-methylol groups in melamine structures, they use the hydrophilic characters of the acid groups to transfer the water repellency feature to the fabric, fibers or material with reverse interaction. When other properties of fabrics and textiles are examined on surfaces coated with these emulsion solutions, it was determined that durability and chemical stability are more durable and their persistence lasts in the longer term. The disadvantage of this method; In addition to factors such as the wear effect of the structure of the material, the fabric is less durable, and also the dyed fabric caused by the chemical structure to change color, in fact, the most important thing is that chemical material release occurs through evaporation as a result of coating the fabric with formaldehyde.

 

1. PARAFFIN BASED PUSHERS

 

The oldest method in which water repellency property is used and formed in fabrics and textiles is production techniques using paraffin-based chemicals. While water repellency is provided at the optimum level in these techniques; oil repulsion cannot be achieved. This emulsion contains aluminum or zirconium salts of fatty acids. These chemicals establish polar-apolar ion balance in the fabrics and help the finish to form a strong bond by allowing the fleece fabric surface and between the fiber to enter and stick more easily. As a result of coating fatty acids containing polar tip parts with metal salts as a result of their interaction with the prepared emulsion solutions, paraffinic solution and hydrophobic parts come together and cause low-cost and homogeneous surfaces with high water repulsion. However, since the chemical stability of these solutions is very low, they are not resistant and cannot be permanent in processes such as dry cleaning and processes involving chemical abrasives such as washing. In addition, since the vapor permeability of paraffins is high in terms of their chemical structure, their use for water repellency is limited.

 

2. STEARIC ACID-MELAMINE BASED PUSHERS

 

When the chemical compounds formed as a result of the reaction of stearic acid and formaldehyde melamine chemical compounds were examined, it was seen that these emulsion solutions were water-repellent solutions and helped to give fabrics or textile products the desired properties. As a result of interacting with each other and also with cellulolysis structures by forming chemical cross-links, the N-methylol groups in melamine structures, they use the hydrophilic characters of the acid groups to transfer the water repellency feature to the fabric, fibers or material with reverse interaction. When other properties of fabrics and textiles are examined on surfaces coated with these emulsion solutions, it was determined that durability and chemical stability are more durable and their persistence lasts in the longer term. The disadvantage of this method; In addition to factors such as the wear effect of the structure of the material, the fabric is less durable, and also the dyed fabric caused by the chemical structure to change color, in fact, the most important thing is that chemical material release occurs through evaporation as a result of coating the fabric with formaldehyde.

 

1. PARAFFIN BASED PUSHERS

 

The oldest method in which water repellency property is used and formed in fabrics and textiles is production techniques using paraffin-based chemicals. While water repellency is provided at the optimum level in these techniques; oil repulsion cannot be achieved. This emulsion contains aluminum or zirconium salts of fatty acids. These chemicals establish polar-apolar ion balance in the fabrics and help the finish to form a strong bond by allowing the fleece fabric surface and between the fiber to enter and stick more easily. As a result of coating fatty acids containing polar tip parts with metal salts as a result of their interaction with the prepared emulsion solutions, paraffinic solution and hydrophobic parts come together and cause low-cost and homogeneous surfaces with high water repulsion. However, since the chemical stability of these solutions is very low, they are not resistant and cannot be permanent in processes such as dry cleaning and processes involving chemical abrasives such as washing. In addition, since the vapor permeability of paraffins is high in terms of their chemical structure, their use for water repellency is limited. 

 

 

 

Thank you,

Bekir Tapan