Production of CuAg/ZnO nanocomposite particles by ultrasonic sprey pyrolysis

Nanotechnology is one of the most popular technology of 21st century, with the help of the basic sciences, nanotechnology has revealed new properties of materials at atomic and molecular scale. Within the scope of the nanotechnology, chemical, physical and biological properties of the nano scale materials are determined and controlled for multifunctional devices and systems. Recently nanotechnology is focus on numerous fields such as; textile applications, aeronautics and space industry, energy, electric-electronic, building and constraction, chemistry, medical, environmental and food engineering. Within following years, it is foreseen that the nanoctechnology market will reach up to trillions of dollars in the world. Nowadays with the help of Turkish Government (Turkish Development Agency and Tübitak), growing number of research centers can be seen in our country. The most popular topics in Turkey's nanotechnology studies are; high-tech ceramics and polymers, thin films, semiconductors and nanocomposites. Nanoparticles have one dimension that measures 100 nanometers or less. Although their macro-sized equivalents obey classical physics theories, because of their dimensions nanostructured materials obey quantum mechanics, quantum laws and theories. The properties of many conventional materials change when formed from nanoparticles. They can gain extraordinary, unique properties as it has size-dependent quantum effects. The main part of the nanotechnology market on the world is synthesis of the nanostructure materials. General knowledge shows that the nanomaterials are produced by nanoparticles, so to discover nanoparticles' properties and understanding the production process of these particles are crucial. There are two main approaches to the general production methods of nano-sized materials. These approaches are "bottom-up" and "top-down" approaches. Top-down approach is based on mechanical crushing for sizing materials to nano sized structures. Examples of top-down approach can be gradable as; high energy ball milling, electrodeposition and lithography. In despite of, bottom-up approach is based on physicochemical principles to deposit atoms or molecules as nano scale structure. Widely- used bottom up approach methods are; sol-gel, inert gas condensation (IGC), flame spray pyrolysis (FSP) and ultrasonic spray pyrolysis (USP). Nanocomposite is the multiphase structure and every phase scale is under 100 nm size. Nanocomposites are different from single phases in many aspects, such as mechanical,magnetic, optical and antibacterial properties. According to the matrix materials, nanocomposite structures are seperated into three main groups. These groups are metal matrix nanocomposites, polymer matrix nanocomposites and ceramic nanocomposites. In the last period, importance of metallic nanocomposite particles increase, because of their multifunctional properties. These properties are conductivity, antibacterial. Amongst the methods of bottom-up approach, ultrasonic spray pyrolysis method comes forward. USP method, which has 4 main steps called aerosol formation, dimension shrinkage, chemical reaction and solid particle collection, is an industrially applied, economic method. The key step is aerosol formation. Ultrasound waves are generated in piezoelectric transducer and transferred into the solution. Due to focusing of ultrasound waves on one point that is called geyser, they can let aerosol drop free in the gas atmosphere. With the help of carrier and reduction gases, aerosol drops will go through the furnace at desired temperature for the chemical reaction. After chemical reduciton step, the final particles are collected in the suitable liquids. USP allows producing different kinds of nanomaterials such as metallic, intermetallic, ceramic, composit nanomaterials which show high purity, spherical and non-agglomerated morphology, homogeneous composition and narrow size distribution. Nanoscale coating is also possible by USP method. There has been lots of researches on application of antifungals and antibacterials on daily life during recent years. Silver and copper ions has become the focus of these intensive research because of their antifungal and antibacterial properties against preventing growth of bacteria and fungis. Copper is known to be used to prevent the formation of algea at the bottom of vessels since very early ancient times. Nowadays it is used to prevent microbial growth in the medical and textile industry. Similar to this, Ag is commonly used as antibacterial agent in the area of textile industry, medical devices, home electric appliances, cosmetics, sporting goods and surface coatings of metals and polymers. In addition to ZnO nanostructures are used in healthcare products on the occasion of its unique properties such as UV blocking capability, high photocatalytic activity and wide range of antibacterial activity .ZnO is a cost effective due to abundance in Earth's crust materials is utilized in food preservation and packaging systems, medical and skin coatings, water purification, bio-imaging and drug delivery In this study, it is aimed to produce spherical AgCu/ZnO nanocomposite particles which has reduced Ag content in accordance with the REACH framework via USP method in a single step by using aqueous solution of metals salts. Further, particle characterization, examining of antifungal and antibacterial properties of nanoparticles by using different application techniques (coating, lamination, impregnating) and contents of different raw materials, woven, knitted and non-woven substrates, and determination of using these nanoparticles in the textile industry (military uniforms, socks, technical textiles, etc.) are the other objectives of project. Original aspect of this study, production of antifungal and antibacterial CuAg/ZnO nanocomposite particles by USP-HR method in a single step, control the particle morphology and investigate the use of different areas of the textile industry. The multifunctional AgCu/ZnO nanocomposite particles with spherical morphology and reduced silver amount depending on REACH Regulations (Registration, Evaulation, Restriction and Authorisation of Chemicals, EC1907/2006) were produced by a simple and cost effective bottom-up approach. The hydrogen reduction assisted ultrasonic spray pyrolysis method was applied at 400 - 800◦C reaction temperatures using 0.025 – 0.4 M aqueous solution of silver/copper/zinc nitrate to prepare nanocomposite particles. The effects of reduction temperature, precursor solution and gas flow rate on the morphology and crystal structure of the AgCu/ZnO nanocomposite particles were investigated. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies revealed that the produced nanocomposite particles sizes are various between 20 nm and 40 nm, with uniform morphologies. The SEM results shows that the produced CuAg/ZnO nanocomposite particles are formed by aggregation of the primary nucleated nanosize particles and shape the secondary particles. Additionally, Cu, Ag, Zn and O were detected in the nanocomposite particle structure by the EDS analyses. X-ray diffraction patterns exhibits that particles consist of Ag, Cu and ZnO phases. X-ray diffraction (XRD) studies showed that the crystallinity of the particles was decreased by decreasing the reduction temperature from 400 oC to 800 oC. The results indicate that the effective reduction temperature was determined as 600 oC and increased Zn2+ amount than the stoichiometric amount in the precursor solution is suitable to produce the appropriate nanocomposite particles with Ag, Cu and ZnO crystallites. CuAg/ZnO nanocomposite particles exhibit improved antibacterial activity (100 %). According to solid medium and liquid medium test methods, they have also antifungal properties. Improved antibacterial (ASTM E 2149-01) and antifungal properties (AATCC 30) of AgCu/ZnO nanocomposite particles demonstrated that such AgCu/ZnO nanocomposite particles could be used as antibacterial and antifungal agents.