نشریه علوم و فناوری رنگ
سال نهم شماره 1 (پیاپی 31، بهار 1394)

Structural colors are one of the interesting aspects of some avian plumages. Due to the unique optical properties، material scientists and engineers always take the nature as the best source of inspiration for novel materials. In this article، some brilliant feathers of a pheasant ‘Colchicus’ were prepared. The electron microscopy، spectrometry، colorimetric analysis and optical modeling were used to study the color of the brilliant barbule''s feathers. A weak iridescence effect was found in the sample''s reflectance spectrum that confirms the structural base of the color. This structure is consisting of both a single thin film and a two-dimensional hexagonal photonic crystal. Optical modeling revealed that the heterostructure can produce a structural color with a green hue.

The present research is defined to clarify the relationship between colour and emotion and to investigate the effects of culture, gender and age on colour emotion. Observers took part in a psychophysical experiment to evaluate the single colour stimuli using “heavy-light”, “warm-cool”, and “active-passive” colour emotional scales. These scales were chosen on the basis of the suggested emotional scales in Li Chen Ou's study. The observers divided into three different groups to investigate the effect of culture, gender and age on the colour emotional scales. The observer groups were female versus male, from Isfahan versus not from Isfahan and 20 to 30 years old versus 35 to 45 years old. Twenty colour stimuli which covered CIELAB colour space, reasonably, were presented on a calibrated LCD in a darkened room. The observers reported their emotional responses of each of the stimuli. The reported data were transformed to scale values using a categorical judgment method. The results showed that the effect of gender, culture and age on the “heavy-light”, “warm-cool” and “active-passive” colour emotional scales is insignificant. Examining the suggested colour emotional model of the previous study conducted by Li Chen Ou, showed the best determination coefficient between visual data and predicted ones for “heavy-light” colour emotional scales by R2=0.74.

In this work, nano silica was modified by Glycidoxy propyl trimethoxy silane at different pH conditions. In order to study the surface treated particles, some testes on particles and poly urethane clear coat containing nano particles were performed. To characterize the particles some tests such as pH, density, FT-IR, elemental analysis and zeta potential were performed.Also in order to study surface chemistry of treated particles, Turbidity of particle in two solvents with different solubility parameters was implemented. The results show that the pH of treating bath, highly affects on amount of grafting. Maximum grafting content was obtained at isoelectric point of silane (4.7) and above isoelectric point of silica (5-6). Grafting silane on silica Surface causes the density of particles decrease and the isoelectric point increases. Sample with higher grafting has better dispersion stability in solvents with higher hydrogen bonding parameter (δH) and lower polar parameter (δP).This phenoma is because of increasing hydrophobisity of treated particles and decrease of polarity. Inorder to quantify interaction of particles with poly urethane matrix, Tensile strength, DMTA and Buchhol Hardness, were performed. The results were representative chemical and physical interaction between treated particles and poly urethane matrix which is increase considerably mechanical properties of nano composite.

In this research, initially modified nano-TiO2 was prepared from salicylic acid. Then, adsorption capacity of Methylene Blue (MB) onto modified nanoparticles was investigated in a batch system by considering the effects of various parameters like contact time, adsorbent dosage, pH, initial dye concentration and temperature. Optimum conditions for MB adsorption were found to be neutral and alkaline pHs, 0.4 g of adsorbent and equilibrium time≈ 50 min. The results showed that the increase of temperature and initial MB concentration leads to gradual decrease of adsorption rate. Evaluation of non-linear adsorption isotherm and kinetic models by Polymath software suggested that data can be well described by the pseudo-second-order kinetic and Freundlich isotherm models. Thermodynamic studies showed that the adsorption process was spontaneous and exothermic.

CdSe (Core) and CdSe/ZnS (Core/Shell) nanocrystals were produced using a green synthesis method by using phosphine- free precursor materials. The optical properties of the produced nanocrystals were investigated using UV- Vis absorption and PL emission spectra, and the average size of the nanocrystals was estimated optically using the absorption data. Size and morphology of the nanocrystals were also investigated using Williamson- Hall analysis and the TEM images. Our results show good agreement among the mentioned three different methods. Thus, size of CdSe nanocrystals was estimated within the 5.5-8.5 nm range. It was shown by X-ray diffraction method that CdSe nanocrystals, with zinc-blende structure, are formed. With increasing the growth time and decreasing the temperature, a red-shift was observed in both absorption and emission edges, which indicates an increase in the size of the grown nanocrystals. After core/shelling the nanocrystals, red-shifts of ~ 10 nm and ~ 30-40 nm were observed in the absorption and emission spectra of the grown nanocrystals, respectively. Accordingly, in our method it was possible to obtain CdSe nanocrystals, with justified green emission, without using octadecene.

In this study, dyeing and fastness properties of acrylic fibers dyed with two naphthalimide fluorescent dye were investigated. The obtained spectrophotometric results of dyed fabrics showed that the used dyes had a good build up and fluorescent intensity on the acrylic fiber. Response surface methodology (RSM) was applied to evaluate the simple and combined effects of the main independent parameters on the optimizing the operating conditions of the dyeing process. The results indicated that the fluorescent intensity, dyeing and fastness properties of acrylic fibers improved with the modification of naphthalimide dye using PAMAM dendrime (G=-0.5).

Polyurethanes due to their excellent properties are used in different industrial applications. Polyurethane and polyurethane-ureas have been used as coating materials in factories ground areas and sport fields during the last decades. But improving their thermal stability was always the major goal for developing their applications. In this study the polyurethane-urea nanocomposites with nanodiamond were prepared by in situ polymerization and their chemical structure, thermal stability, glass transition temperature and also crystallinity were measured. The results showed 13˚C improvement in thermal stability by using only 0.1% of nanodiamond in polymer matrix. Glass transition temperature (Tg) was also increased and soft segment crystallinity was decreased by addition of nanodiamond in polymer matrix.

Sukias house is located in Tabriziha neighborhood, Isfahan, Iran. Investigators have revealed that this historical house has been built during Shah Abbas II (r. 1632-1666). One of the most important decorations of this building is its historical wall paintings. The paint layer of wall painting is generally composed of pigments, organic binding media and other additives. Characterization of the binding media is a challenging problem in cultural heritage due to the presence of complex materials structure of wall paintings. The principal aim of this work is to overcome the spectral interferences for interpretation of FTIR spectra obtained from wall paintings samples. A set of calibration samples were prepared in a similar way to the strata of a real wall painting from lowest to highest complexity. Sampling from the Sukias house was accomplished as well. Each sample was analyzed by FTIR spectroscopy and spectral data set was processed by chemometrics approaches. Binding medium of Sukias house was identified as egg yolk. Results are promising in the sense that SIMCA could be useful to mine the complex FTIR spectra and characterize binding media in wall paintings which is very time-consuming and challenging by regular methods of analysis.

In this study the correlation between quantitative visual assessment of distinctness of image and its instrumental equivalents as measured by two types of measuring instruments namely a goniophotometer and a wavescan DOI instrument was sought after. To this end, 4 scales were prepared based on automotive achromatic samples varying in lightness i.e. black, grey, silver and white, having variable DOI values but the other geometric attributes being kept constant as far as possible. The differences in DOI of samples in each scale were visually assessed and quantified in terms of an also prepared lightness scale by a panel of 16 observers. The coefficient of determination was utilized to assess the correlation between such quantified visually assessed data and the equivalent instrument values as measured separately by a goniophotometer and a wavescan DOI instrument. Results show that irrespective of lightness of samples, the correlation of differences in visual and instrumental data was always superior for the goniophotometer than the wavescan DOI instrument. This implies that the measurement of DOI by a goniophotometer has unequivocal advantages.