نشریه مطالعات در دنیای رنگ
سال ششم شماره 1 (پیاپی 20، بهار 1395)

Polymer solar cells commonly are made of optically active thin film between two electrodes. Film forming technique such as spin coating, doctor blading and casting are used currently for high volume optically active layers production. From a processing point of view, other film-forming techniques such as gravure coating, off-set coating, spray coating and printing technique such as inkjet printing, pad printing and screen printing are favorable to the formation of thin film for polymer solar cells. In this paper, entire process leading to polymer solar cells are investigated with focus on the materials, available techniques and particular advantages and disadvantages associated with each case

Water-born acrylic emulsions are used in many applications such as Building paints, traffic coatings and adhesives. The reason of increasing the widespread use of them includes reducing in environmental pollutions because of the low amount of organic volatile compounds (voc) and its low prices. Acrylic emulsion film shows good resistance against environmental conditions, ultraviolet radiation and possess high gloss surface, nevertheless acrylic emulsion coatings have some disadvantages which modified by some methods for improving the performance of acrylic resin including use of Nano materials, mixing with polyurethane, fluorinated compounds and inorganic silicones and Modification method depending on the forces between poly (acrylate) and secondary matter, it can be done chemical or physical. This article reviews several modification methods for poly (acrylate) s.

Due to the reduction of energy resources and the need for savings in consumption, thermal barrier coatings in construction and various industries have been considered. Polymeric thermal barrier coatings are a branch of insulation coatings which for use of suitable reinforcement in the polymeric matrix can contain properties such as low thermal conductivity, high thermal resistance and are low absorption coefficient. Operation and easy application of polymeric insulation coatings are other benefits that have increased the interest to these coatings. If one of the components in this composition was in nano scale, nanocomposite thermal insulation coatings will be prepared. In this article, we will briefly mention nanocomposite coatings for low thermal conductivity and heat transfer rules govern mathematical models of these coatings will be discussed.

Solar cells always are considered as clean and low-cost resources of electrical energy by researchers. Typical solar cells are fabricated on inflexible and fragile of glass substrates. Theses solar cells have not performance in aspect of flexibility. So, design and fabrication of solar cells that are fabricated on flexible substrate are very important for researchers. Fiber-shaped solar cell is one of the flexible solar cells that is fabricated on flexible substrates such as metallic wires and polymeric fibers. These solar cells are divided to three groups: 1. Dye sensitized fiber-shaped solar cells 2. Polymeric fiber-shaped solar cells 3. Perovskite fiber-shaped solar cells. This paper briefly reviewed fiber-shaped solar cells, structure, performance, limitations and challenges in this field.

Surface etching technique is commonly used for industrial decoration of glasses. Hydrofluoric acid (HF) solutions or pastes, pure or mixed with other chemicals, are employed as strong corrosive agents to engrave chemically the glass surface. In the wet etching method protective layers as masks are required extensively to prevent the flow of corrosive liquids to undesired regions. Here, in this study, the corrosive etching technique on different surfaces, and the corresponding processes with their required tools are introduced. In continuation, the mask property requirements are discussed. They include topics such as; interfacial adhesion, and chemical resistances properties to acid and corrosive paste, relevant glass masking techniques, uniformity of the mask film and mask removal or the dissolution by appropriate solvents. Lastly, conventional protective coatings in wet etching of glass are introduced.

Pigments are chemical compounds that absorb light in the wavelength range of the visible region. There are four main classified groups of plants pigment including Chlorophyll, Carotenoids, Flavonoids, and Anthocyanin which have different characteristics. Chlorophyll and Carotenoids are insoluble in water and are found in organelles of cells, while the Flavonoids are water-soluble pigments present in vacuole and cytosol. Various novel techniques including ultrasound-assisted extraction, microwave-assisted extraction, supercritical fluid extraction, and accelerated solvent extraction have been developed for the extraction of nutraceuticals from plants in order to shorten the extraction time, decrease the solvent consumption, increase the extraction yield, and enhance the quality of extracts.