The mitigation of corrosion and biofouling is a challenge. Through application of chemicals and special techniques can slow these undesired processes, an effective resolution requires a multidisciplinary approach involving scientists, engineers, and metallurgists. In order to understand the importance of the use of nano-and microlayers as well as selfhealing coatings, the basic concepts of corrosion, corrosion mechanisms, corrosion inhibition and the microbiologically influenced corrosion will be summarised. The preparation, characterization and application of Langmuir-Blodgett and self assembled nanolayers in corrosive and microbial environment will be discussed. Preparation and characterization of microcapsules/ microspheres and their application in coatings will be demonstrated by a number of examples.Keywords: nano-and microcoating, self-healing, slow-release, anticorrosion, antifouling IntroductionCorrosion is a well-known problem all over the world. It consumes a significant part of the gross national product (GDP) of developed and developing countries. A number of authors have provided comprehensive introductions to corrosion mainly in aqueous and wet environments (Jones, 1991;Kaesche, 2003; McCafferety, 2010). Corrosion is the destructive result of the chemical/electrochemical reactions between metals and the environment. Corrosive reactions involve water in either liquid or condensed phases. Most corrosion reactions are electrochemical processes. These involve electron or charge transfer in aqueous solution which leads to metal dissolution (anodic reaction). Depending on the pH of the solution, either hydrogen or hydroxonium ions evolve, resulting in oxides, oxyhydroxides, hydroxides and salts formed on the metal surface (cathodic reaction). The electrochemical potential or electron activity affects the rate of corrosion reaction. To understand corrosion it is necessary to discuss briefly the types of corrosion and the reactions involved.Corrosion occurs in various forms.-Uniform corrosion: The metal surface must be compositionally uniform; the aggressive environment has the same access to all parts of the metal. This type of
2 pH and CO 2 sensing by curcumin coloured cellophane test strip ABSTRACTCurcumin coloured cellophane test strip -fabricated without any synthetic material -is used to determine in situ the instantaneous pH changes in liquids and in the air. A low cost, portable sensor array for possible medical and food-industrial application is developed. Next to the pH detection, curcumin coloured test strip can be applied as CO 2 monitoring sensor, too. On-going processes and the structural changes are followed by UV-VIS spectrophotometer, ATR-FTIR and AFM.
13Concern on different food colours has a rising tendency in the last decades. Many times the 14 labelled ingredients of a food product don't reflect the real composition. To expose products The presence of synthetic dyes in food shows a potential health risk, as several diseases 35(allergy, asthma, hyperactivity and even cancer) are directly linked to the use of these colours Cellophane, which is a thin, transparent, regenerated cellulose film produced from sodium 52 cellulose xanthate (Laity et al. 2000), has been an important industrial material for many 53 years. It is a well-known hydrophilic, water insoluble natural polymer -this property is 54 related to its crystallinity and the intermolecular hydrogen bonding between its hydroxyl 55 groups (Tome et al. 2011; Canas et al. 2002). 56It is used as packaging material for food and confectionary products (candies, cheese and 57 baked goods), and due to its good mechanical properties and hydrophilicity it finds 58 applications in industry (membranes for batteries) (Tome et al. 2011;Beach et al. 2000), and 59 medicine (semipermeable membranes for haemodialysis -since cellophane allows the 60 diffusion of ions and low molecular weight solutes but it does not permit the diffusion of 61 proteins or high molecular weight macromolecules) (Tome et al. 2011; Canas et al. 2002). 62Although nowadays its pre-eminence in the packaging industry has been largely superseded 63 by the oriented polypropylene film, cellophane still has special uses due to its physical 64 properties, which confer advantages compared to other polymers (Laity et al. 2000). 66Compared to cellulose, it has a differentiated 'skin-core' layer structure, with relatively thin, 67 dense skin on both side of the thicker, porous core (Fig. 1A). The swelling of cellophane in 68 water is well known, reaching equilibrium within a period of 2 hours, with no further changes 69 in dimensions. The thickness of the cellophane is 26 ± 1μm as received, 68 ± 2μm fully 70 swollen with water (Laity et al. 2000). 72Cellophane is transparent both to ordinary and UV-light; it exhibits the anisotropic properties 73 of cellulose due to its two optical axes and it has excellent dielectric properties. Per se it is not 76The goal of the present study is to build a quick, qualitative food colour test method using the ,3,3-trimethyl-2-[(1E,3E,5E,7E,9E,11E,13E,15E, 17E)-3,7,12,16-tetramethyl-18-(2,6,6-trimethylcyclohexen-1-yl)octadeca-1,3,5,7,9,11,13, 15,17-nonaenyl] The tested foods, beverages and special colours are listed in Table 3. Food products as soups colours the test strip, too (Fig. 1). The colouring effect is based on physisorption of the dye molecules in the swelled cellophane 146 capillaries ( Fig. 1Ab and 1Ac). Authors conjecture that the differences in the chemical 187 trisodium (4E)-5-oxo-1-(4-sulfonatophenyl)-4-[(4-sulfonatophenyl)hydrazono]-3-pyrazolecarboxylateFirst instant soups are tested and the absorbance spectra are compared to absorption spectrum 188 of curcumin (Fig. 4) In both cases ...
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