Synthesis Of Proton Exchange Membrane By Atrp And Iniferter Methods.

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2013Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 20131950’li yıllarda General Electric tarafından bulunan PEM teknolojisi, o yıllarda ilk defa NASA tarafından Gemini uzay aracında güç ünitesi olarak kullanılmıştır. Günümüzde PEM yakıt pilleri otomotiv sektöründe içten yanmalı motorlara alternatif olarak geliştirilmekte ve kullanılmaktadır. Proton değişim membran yakıt hücreleri, özellikle yüksek performanslı polimerlerin bulunmasından sonra; uzay çalışmalarında ve özel askeri sistemlerde uygulanmak amacıyla geliştirilmiştir. Günümüz teknolojisi ile hertürlü güç gereksiniminin olduğu yerlerde kullanılmakta ve yaygınlaşnmaktadır. Proton değişim membran yakıt hücreleri düşük çalışma sıcaklığında yüksek verim elde edilmesi, sessiz çalışması ve saf suyun dışında herhangi bir atık ortaya çıkarmamasından dolayı en çok ilgi çeken yakıt hücresi türüdür. PEM yakıt hücrelerinin temel bileşeni anot ve katot olmak üzere iki tane elektrot içerir. Bunlar birbirlerinden polimer membran elektrolit ile ayrılmışlardır. Her iki elektrot bir kenarlarından ince platin katalizör tabakası ile örtülmüştür. Yakıt olarak kullanılan hidrojen yakıt hücresinin anot kenarından beslenir. Anotta platin katalizör varlığında serbest elektronlar ve protonlara ayrışır. Serbest elektronlar dış çevrimde kullanılırlar ve elektrik akımını oluştururlar. Protonlar polimer membran elektroliti geçerek katota doğru hareket ederler, katotta havadan gelen oksijen dış çevrimden gelen elektronlar ve protonlar saf su ve ısı oluşturmak üzere birleşirler. Tek bir yakıt hücresi yaklaşık 0,6 volt güç üretir, istenilen elektriksel güç miktarını karşılamak için yakıt hücreleri birleştirilirler. PEM yakıt pillerinde, elektrotlar karbon yapılı olup, kullanılan elektrolit ise ince bir polimer membrandır. En çok kullanılan membran, poli[perflorosülfonik] asit veya Nafyon’dur. Bu ince polimer tabakadan protonlar kolayca diğer tarafa geçebilirken, elektronların geçişi mümkün değildir. Hidrojen anot üzerine akarken, elektrot yüzeyinde hidrojen iyonlarına (proton) ve elektronlarına ayrılır. Oluşan hidrojen iyonları ince membrandan katoda doğru ilerlerken, geçişi engellenen elektrotlar dış devreden geçerek güç oluştururlar. Havadan sağlanan oksijen katot üzerinde hidrojen iyonları ve dış devreden gelen elektronlar ile birleşerek suyun oluşmasını sağlar. PEM yakıt pili elektrotları üzerinde gerçekleşen reaksiyonlar aşağıdaki gibidir; H2 (g) → 2H+ + 2e- anot tepkimesi 2H+ + 2e- + 1/2O2 → H2O katot tepkimesi PEM yakıt pilleri 80°C sıcaklıkta çalıştıklarından ve bu sıcaklık, gerçekleşen elektrokimyasal reaksiyonlar için düşük olduğundan elektrotlar ince platin tabakaları ile desteklenmektedirler. PEM yakıt pillerinin otomotiv sektöründe kullanımını sağlayan önemli avantajları vardır. Bu avantajlar; küçük boyutta uygulanabilirlikleri, düşük sıcaklıklarda çalışmalarına rağmen bu sıcaklıklardan kolayca yüksek güç üretimine geçebilmeleridir. Bunların yanında, yüksek verimde çalışmaları, % 40-50 seviyesinde maksimum teorik voltaj üretebilmeleri ve güç ihtiyacındaki değişikliklere hızlı cevap verebilmeleri de PEM yakıt pillerini tercih edilir konuma getirmektedir. Proton değişim membran yakıt hücrelerinin en önemli elemanı proton iletim özelliğine sahip polimerik membrandır. Yakıt hücreleriyle ilgili yapılan çalışmaların başında polimerik membranların geliştirilmesi ile ilgili olan çalışmalar yer almaktadır. Günümüzde ticari olarak kullanılan membranların çeşitliliğinin az ve fiyatlarının yüksek olmasından dolayı alternatif membranların geliştirilmesi ile ilgili çalışmalar oldukça hızlanmıştır. Proton değişim membran yakıt hücrelerinde kullanılan membranların; • • Proton geçirgen özellikte olması, • • Su, yakıt (hidrojen veya metanol), oksijen ve havadaki diğer gazları geçirmemesi • • Mekanik dayanımının yüksek olması, • • Uzun süreli kullanımda ısıl ve kimyasal direnci yüksek, • • Teknolojik olarak yaygın bir şekilde kullanılabilmesi için emniyetli ve ucuz olması gerekmektedir Proton değişim yakıt hücrelerinde kullanılan membranların yüksek verimle çalışabilmeleri için su ile tamamen doyurulmuş olmaları gerekmektedir. Yapılan çalışmalarda membranın tam doygun olduğu zaman yüksek iyonik iletkenliğe ulaşıldığı görülmektedir. Membran çok ince bir yapıya sahip olmasına rağmen çok etkili bir gaz ayrıştırıcıdır. Hidrojen yakıtı, oksidant havadan ayırıp ayrı tutabilme kabiliyetine sahip olup bu özellik yakıt pilinin çalışma verimine esas oluşturmaktadır. Membran iyonik iletken olmasına rağmen elektronları geçirmez. Organik doğası gereği elektronik yalıtkandır. Bu durum ise yakıt pilinin çalışmasının diğer bir esasıdır. Plakadan geçmeyen elektronlar, harici bir devre yardımıyla hücrenin diğer tarafına (katot) alınır ev devrelerini tamamlarlar. Bu çalışmada ana zincir olarak PVC kullanılıp, bu polimere sülfon grubu içeren AMPS monomeri aşı kopolimerizasyonu ilebağlanmıştır. P(VC-g-AMPS) aşı kopolimerinin sentezlenmesi için iki farklı polimerizasyon çeşidi kullanılmıştır. Bunlar ATRP ve iniferter polimerizasyon metotlarıdır. ATRP çok yönlü kontrollü radikal polimerizasyon metotlarından biridir. Bir ATRP sistemi; başlatıcı, metal halojenür, ligand ve monomerden oluşmaktadır. Düşük oksidasyon basamağına sahip metal kompleksi (Mtn compleks/Ligand), radikal ve daha yüksek oksidasyon basamağına sahip metal kompleksi (X-Mtn+1/Ligand) üretmek üzere alkil halojenür (R-X) ile reaksiyona girer. Oluşan radikal monomere eklenir ve böylece polimer zincirinde büyüme gerçekleşir. Reaksiyonun ilerleme aşaması halojenürün koparılması sonucu oluşan serbest radikal üzerinden ilerler. Serbest radikal metalden halojenürü tekrar koparır ve aktif olmayan ürün oluşur. Bu işlemler oldukça hızlıdır ve reaksiyonda denge aktif olmayan ürün oluşumu yönündedir. Aktivasyon ve deaktivasyon hız sabitlerinin oranına bağlı olarak bir süre sonra büyüyen zincir yine aktif hale gelir ve büyümeye devam eder. Bu basamaklar tekrarlanarak kontrollü zincir büyümesi sağlanmış olur. Sonlanma tamamen önlenemez, ancak sonlanan zincirlerin oranı büyüyen zincirlerle karşılaştırıldığında sonlanan zincirlerin sayısı oldukça küçüktür. ATRP reaksiyonu ortamdaki monomer bitene kadar ya da reaksiyon koşulları bozulana kadar devam eden bir yaşayan polimerleşme tekniğidir. İstenilen ağırlıkta polimer elde edene kadar reaksiyon devam edebilir ve reaksiyonu durdurmak için dışarıdan müdahale gerekmektedir. Bu çalışmanın ATRP basamağında, PVC makro başlatıcı olarak kullanılmış ve PVC ye ait klor gruplarından reaksiyon gerçekleşmiştir. Diğer yöntem olan iniferter polimerizasyonu ise bir iniferter grubun ışık veya ısı ile radikal üretmesi ve monomerin başlatıcı radikali ile kontrollü mekanizmayı sağlayan sonlandırıcı radikal grubunun arasına dolması ile gerçekleşir. Bu kontrollü radikal polimerizaston tipi ilk olarak 1982 yılında Otsu ve Yoshida tarafından gerçekleştirilmiştir. Monofonksiyonel fotoiniferter BDC (Benzil-N,N-dietilditiyokarbomat) ve bifonksiyonel fotoiniferter XDC (Ksilen bis N,N-dietilditiyokarbomat) bazı monomerlerin yaşayan polimerizasyonları için kullanılmıştır [49]. Bu çalışmada iniferter grup olarak, sodyum dietilditiyokarbomat kullanılmıştır. Makrobaşlatıcı olarak önce PVC ile sodyum dietil ditiyokarbomat reaksiyona sokulmuş ve PVC-DDC makrobaşlatıcısı sentezlenmiştir. Ardından ışık ile PVC üzerinde bulunan DDC gruplarından iniferter polimerizasyonu gerçekleştirilmiş ve istenen P(VC-g-AMPS) aşı kopolimeri elde edilmiştir. İki farklı metotla sentezlenen P(VC-g-AMPS) aşı kopolimeri FT-IR, UV-Visible, DSC, 1H NMR, klasik GPC ve üçlü dedektör GPC sistemleri ile karakterize edilmiştir. Sentezlenen maddelerin iyon iletkenlikleri Elektrokimyasal Empedans Spektrometresi ile incelenmiştir.The proton exchange membrane fuel cell (PEMFC) uses a water-based, acidic polymer membrane as its electrolyte, with platinum-based electrodes. PEMFC cells operate at relatively low temperatures (below 100 degrees Celsius) and can tailor electrical output to meet dynamic power requirements. Due to the relatively low temperatures and the use of precious metal-based electrodes, these cells must operate on pure hydrogen. PEMFC cells are currently the leading technology for light duty vehicles and materials handling vehicles, and to a lesser extent for stationary and other applications. The PEMFC fuel cell is also sometimes called a polymer electrolyte membrane fuel cell (also PEMFC). Fuel cells have various advantages compared to conventional power sources, such as internal combustion engines or batteries. Although some of the fuel cells attributes are only valid for some applications, most advantages are more general. Fuel cells have a higher efficiency than diesel or gas engines. Fuel cells can eliminate pollution caused by burning fossil fuels; for hydrogen fuelled fuel cells, the only by-product at point of use is water. If the hydrogen comes from the electrolysis of water driven by renewable energy, then using fuel cells eliminates greenhouse gases over the whole cycle. Fuel cells do not need conventional fuels such as oil or gas and can therefore reduce economic dependence on oil producing countries, creating greater energy security for the user nation. Since hydrogen can be produced anywhere where there is water and a source of power, generation of fuel can be distributed and does not have to be grid-dependent. The use of stationary fuel cells to generate power at the point of use allows for a decentralised power grid that is potentially more stable. Operating times are much longer than with batteries, since doubling the operating time needs only doubling the amount of fuel and not the doubling of the capacity of the unit itself.Yüksek LisansM.Sc

Hybrid polymeric materials comprising clay nanotubes, photothermal agents and phase change materials for food, water and energy applications

In this thesis, different fundamental solutions have been offered on the concepts of ''saving food'', ''saving water'' and ''saving energy'' by preparing hybrid composite systems comprising different combinations of clay nanoparticles, photothermal agents and phase change materials. For the protection of food products, two main approaches were presented to prolong the shelf life of packaged food in the marketing and transportation stages. The first solution offered was the design of active food packaging materials with halloysite nanotubes having ethylene scavenging properties for the storage of fruits and vegetables. The second solution offered was the design of a food packaging material comprising halloysite nanotubes loaded with phase change materials that can buffer temperature fluctuations during the cold-chain transportation of food products. The particle quality of halloysite nanotubes were determined to play a critical role in these studies, which has led to an in-depth investigation of the effect of homogeneous size distribution and agglomeration-free quality of halloysite nanotubes on their loading/surface functionalization capacity and efficiency as reinforcing fillers in polymer nanocomposites. A novel three-step nanoparticle separation method was developed based on the surface modification of halloysite nanotubes with polydopamine, resulting in agglomeration-free halloysite nanotubes sorted in different size ranges. The surface modification of particles with polydopamine was further extended to a new material design that utilizes the light to thermal energy conversion capability of polydopamine. Waterborne polyurethane particles synthesized in the form of aqueous dispersions were coated with polydopamine, resulting in hybrid polydopamine-polyurethane dispersions. Films cast from these dispersions intrinsically showed light to thermal energy conversion ability and were demonstrated to have a huge potential in water purification by solar driven evaporation. Promising results obtained with polydopamine-polyurethane hybrid films led us to produce a multifunctional hybrid material that has solar to thermal energy conversion, thermal energy storage and thermal buffering properties. As a preliminary work to reach this goal the shape-stable latent heat storage concept was examined by using a zeolitic shape stabilizer and phase change materials. The acquired knowledge from this study was utilized to prepare form-stable phase change films by using the photothermal polydopamine-polyurethane polymer matrix and PEG4000 as phase change materials. In this study, PEG4000 was directly integrated into the polymer matrix at different ratios by dissolving in the aqueous polydopamine-polyurethane dispersion, resulting in form-stable phase change films, which present unique energy storage properties and have strong potential as thermoregulating materials

Effect of size-graded and polydopamine-coated halloysite nanotubes on fundamental properties of low-density polyethylene nanocomposite film

In this study, some of the critical fundamental properties, which are holding importance in usage areas, of low-density polyethylene (LDPE) film were studied by embedding size-graded and polydopamine-coated halloysite nanotubes into the polymer matrix. This concept evaluated the importance of the well-dispersion of nanoparticles in the composite system and interfacial adhesion between nanofiller and polymer matrix on the degree of crystallinity and mechanical properties. For this purpose, halloysite nanotubes, coated with polydopamine and size graded afterward, were integrated into the LDPE matrix by the twin-screw extrusion process, following which, nanocomposite films were prepared by film-blown technique. Both effects of halloysite nanoparticles, having the polydopamine layer on their surface and size-graded, on properties such as mechanical strength, thermal feature, and degree of crystallinity, of those directly acting on the usage goals of LDPE-based films, were tested

Thermally buffering polyethylene/halloysite/phase change material nanocomposite packaging films for cold storage of foods

Nanocomposite flexible food packaging films that prolong the time that frozen or chilled food products stay cold are demonstrated. Nanohybrids of phase change materials (PCMs) and halloysite nanotubes (HNTs) were prepared as nanofillers with thermal buffering performance. HNTs were impregnated with polymeric PCMs, PEG400 and PEG600, resulting in a mixture of form-stable HNT/PCM nanohybrids that presented consecutive melting transitions in the temperature range of -22 degrees C - 22 degrees C. The incorporation of the mixture of HNT/PEG400 and HNT/PEG600 nanonybrids into polyethylene (PE) matrix by melt compounding resulted in flexible nanocomposite films that have acceptable mechanical properties for use in food packaging applications and presented a broad melting transition from -17 degrees C to 26 degrees C with a latent heat of 2.3 J/g. The thawing rate of frozen nanocomposite films at room temperature was less than half of the thawing rate of neat PE films. Furthermore, nanocomposite films delayed the warming of frozen and chilled samples for 18 min and 20 min, respectively, relative to neat PE films. Nanocomposite films composed of PCM impregnated HNTs demonstrated here are the first examples of flexible food packaging films with significant thermal buffering capacity in cold chain temperatures and have a great potential to enhance food quality and food safety in cold-chain storage and transportation

Polydopamine-coated halloysite nanotubes for sunlight-triggered release of active substances

A sunlight-triggered controlled release system comprising environmentally friendly components is presented herein. The combination of a photothermal nanocarrier that can be remotely heated by sunlight and a heat-activatable stopper that can be removed via sunlight-triggered heating of the nanocarriers resulted in a smart controlled release system. Surfaces of halloysite nanotubes (HNTs) were coated with a polydopamine (PDA) layer to create a photothermal nanocarrier that heats up when irradiated with sunlight. The resulting HNT-PDA nanocarriers were impregnated with carvacrol, a volatile essential oil as a model active substance, and were further functionalized with lauric acid, as a stopper layer. The presence of lauric acid hindering the carvacrol release from HNT-PDA nanocarriers was confirmed by differential scanning calorimetry and transmission electron microscopy imaging. HNT-PDA nanocarriers were shown to be heated to 45 °C upon sunlight irradiation for 10 min, demonstrating that their sunlight activation can trigger the melting of the lauric acid stopper. In the absence of the light trigger, the lauric acid stopper slowed down and hindered the carvacrol release. Only 40% of impregnated carvacrol was released from the lauric acid-functionalized nanocarriers in 60 days, whereas all carvacrol molecules were released in 30 days when the lauric acid stopper was not present. Release of carvacrol molecules that were entrapped in the HNT-PDA nanocarriers with the lauric acid stopper was shown to be controlled with sunlight. 10-15% of impregnated carvacrol molecules were released upon sunlight irradiation for 6 h, and carvacrol release stopped when the sunlight irradiation was turned off, where 92% of all carvacrol was released over 6 consecutive light-on/light-off cycles. The presented clay nanotube-based controlled release system comprising a photothermal nanocarrier and a heat-activatable stopper demonstrated excellent sunlight-triggered release behavior and therefore can be utilized in various applications requiring remote control of active substance release

Lysostaphin-functionalized waterborne polyurethane/polydopamine coatings effective against S. aureus biofilms

Hybrid waterborne polyurethane/polydopamine (WPU/PDA) matrix, showing the adhesive properties of PDA in its entirety, was utilized for the immobilization of lysostaphin (Lys), an important anti-staphylococcal agent, to obtain highly effective antibacterial and antibiofilm surface coatings. WPU/PDA matrix prepared by the encapsulation of WPU particles with PDA in aqueous dispersion was applied as coatings on substrates, and the facile incubation of the WPU/PDA-coated surfaces with Lys in aqueous solution resulted in WPU/PDA/Lys coatings that contained immobilized Lys on the surface. WPU/PDA/Lys coatings showed strong anti-Staphylococcus aureus activity with a 4 log reduction in the number of cells. Furthermore, WPU/PDA/Lys coatings were demonstrated to be durable without any enzyme leakage, and their antibacterial activity was preserved for at least 30 days and over multiple exposures to bacteria. WPU/PDA/Lys coatings presented significant antibiofilm activity against S. aureus with a 3.5 log reduction in the number of surface-attached bacteria. WPU/PDA/Lys coatings that are easy-to-apply to almost any surface, non-toxic, and environmentally friendly provide promising antibacterial and antibiofilm surfaces that are effective against S. aureus

NIR-responsive waterborne polyurethane-polydopamine coatings for light-driven disinfection of surfaces

Apart from conventional chemical-based methods, alternative disinfection methods that can physically destroy bacteria are needed. Here, biocompatible, non-toxic, environmentally friendly hybrid coatings prepared from dispersions of polydopamine-coated waterborne polyurethane particles (WPU-PDA) that offer effective light-to-heat conversion were designed to eradicate pathogenic bacteria and biofilms using photothermal therapy. The resulting WPU-PDA hybrid coatings demonstrated an effective photothermal activity by reaching 155 °C under 4 min NIR-laser irradiation and staying stable upon multiple irradiation cycles. WPU-PDA coatings induced hyperthermia on S. aureus resulting in a 3.5 log reduction of viable cells with a killing activity that is stable for at least 20 contamination/disinfection cycles. Furthermore, the prepared coatings were shown to have antibiofilm properties resulting in a 3 min NIR-light activated 3.9 log reduction in the viability through physical disruption of biofilm bacteria. Light-activated antibacterial/antibiofilm coatings demonstrated here provide a strong potential for NIR-light activated disinfection of surfaces

Waterborne polydopamine-polyurethane/polyethylene glycol-based phase change films for solar-to-thermal energy conversion and storage

Form-stable phase change films composed of a polydopamine-polyurethane polymer matrix with photothermal conversion properties and polyethylene glycol (PEG) are presented. Surfaces of environmentally friendly waterborne polyurethane (WPU) particles in aqueous dispersions were coated with polydopamine to create a stable waterborne dispersion of a polydopamine-polyurethane (PDA-WPU) matrix, which intrinsically presents significant photothermal conversion properties, and PEG was directly integrated into the PDA-WPU matrix by simple mixing in the dispersion form. Successful film formation was achieved at PDA-WPU to PEG ratios of 1:1 and higher by weight, resulting in form-stable, homogeneous PDA-WPU/PEG phase change films. Incorporation of PEG into the amorphous PDA-WPU matrix was demonstrated to impart a semicrystalline character to PDA-WPU films, which also increased their thermal stability and thermal conductivity. Young's modulus of PDA-WPU/PEG films increased while the tensile strength and elongation at break values decreased as a function of PEG content, yet all films showed a flexible behavior. For the films prepared with the highest amount of PEG (PDA-WPU:PEG 1:1), the melting and solidifying enthalpies were calculated to be 81.1 and 77.9 J/g, respectively, and enthalpies remained the same over 60 consecutive heating-cooling cycles. The temperature of the PDA-WPU:PEG 1:1 film reached 74.8 °C under 20 min of solar irradiation at 150 mW/cm2 with a solar-to-thermal energy conversion efficiency of 72.9%. In a cold environment, PDA-WPU/PEG films and their surroundings were shown to heat up more than controls under solar light and stay warmer after the solar irradiation was stopped. The temperature of the environment surrounded with the PDA-WPU/PEG film increased 10 °C more than the temperature of the control environment under 30 min of sunlight irradiation. Upon switching the sunlight irradiation off, the PDA-WPU/PEG environment cooled down to ambient temperature 10 min later than the control environment, demonstrating that these form-stable, flexible, and durable films can efficiently harvest and store sunlight and have strong potential as solar-driven thermoregulating materials

Purification and sorting of halloysite nanotubes into homogeneous, agglomeration-free fractions by polydopamine functionalization

Halloysite nanotubes (HNTs) have attracted great attention in the field of nanotechnology as natural, high value-added nanomaterials. Despite their significant potential as carriers of active agents and fillers in nanocomposite structures, inhomogeneity of HNTs in terms of length and diameter along with their a lomeration tendency poses important obstacles for the utilization of them in a wider range of applications. Here, a facile, three-step separation protocol that allows the sorting of HNTs into agglomeration-free, uniform size fractions is reported. The protocol consists of coating of HNTs with polydopamine to impart hydrophilicity and aqueous dispersibility, followed by their ultrasonication and centrifugation at varying velocities for size-based separation. Particle size distribution analysis by scanning electron microscopy and dynamic light scattering has demonstrated that the separation protocol resulted in uniform HNT fractions of varying agglomeration states and particle sizes. The highest quality fraction obtained with 18% yield was free of agglomerations and consisted of HNTs of uniform lengths and diameters. The polydopamine coating on HNTs which facilitated the separation was demonstrated to be removed by a simple heat treatment that preserved the crystal structure of HNTs. The impact of the separation protocol on the loading and functionalization capacity of halloysites was investigated. Highest quality HNTs presented 4.1-fold increase in lumen loading and 1.9-fold increase in covalent surface coupling ratios compared to the loading and functionalization ratios obtained with raw HNTs. Similarly, sorted, high-quality HNTs were demonstrated to be better dispersed in a polymeric matrix, resulting in polymeric nanocomposites with significantly enhanced mechanical properties compared to nanocomposites prepared with raw HNTs. The three-step separation protocol presented here provides a toolbox that allows sorting of raw HNTs into uniform fractions of different size ranges, from which HNTs of desired qualities required by different applications can be selected

Carvacrol loaded halloysite coatings for antimicrobial food packaging applications

Antimicrobial thin film coatings that can be utilized in food packaging provide an effective approach to enhance food quality and safety. Here, the coating of polyethylene films with an antimicrobial thin film through a Layer-by-Layer (LbL) assembly is demonstrated. Halloysite nanotubes (HNTs) which are tubular clay nanoparticles were utilized for the encapsulation and sustained release of carvacrol, the active component of essential thyme oil. Antimicrobial thin film coatings of 225 nm thickness were prepared by the deposition of ten bilayers of chitosan (CHI) and carvacrol loaded HNTs onto the polyethylene surface by spray LbL. Coated films reduced the viability of a food pathogen, Aeromonas hydrophila by 85% and the aerobic count on chicken meat surfaces by 48%. Furthermore, coated film surfaces demonstrated lower bacterial attachment compared to control polyethylene films indicating their antibiofilm character. Composed of natural and safe components, antimicrobial coatings developed in this study provide a novel and effective approach to obtain antimicrobial food packaging materials that can greatly contribute to food safety