Martina Viková

UV protection properties of silk fabric dyed with eucalyptus leaf extract

A natural dye extracted from eucalyptus leaves was applied to a silk fabric using two padding techniques, namely the pad‐batch and pad‐dry techniques, under different conditions. It was observed that with an increase in the dye concentration, the ultraviolet (UV) protection factor (UPF) values ranged between good and excellent for the silk fabric. In addition, a darker colour, such as that provided by a FeSO4 mordant, gave better protection because of higher UV absorption. A silk fabric dyed in a solution containing the eucalyptus leaf extract showed a shade of pale yellowish‐brown. The exception was when the fabric was dyed with the FeSO4 mordant, resulting in a shade of dark greyish‐brown. The colour fastness to washing and rubbing of the silk fabrics treated with the mordant after dyeing was investigated and the results showed good fastness, whereas colour fastness to light was at a fair level. The results confirmed that natural dyes from eucalyptus leaf extract with metal mordants have potential applications in fabric dyeing and in producing UV‐protective silk fabrics.

Effect of carbon black nanoparticles on reflective behavior of printed cotton/nylon fabrics in visible/near infrared regions

Tuning the level of visible and near infrared (NIR) reflectance of textile surfaces is crucial for making them undetected in each environment. In this regard, samples of cotton/nylon fabrics were printed using a mixture of some special pigments and carbon black (CB) nanoparticles to produce brown, olive green and khaki shades which are present in concealment patterns of textiles employed in deserts. The effect of CB nanoparticles on Vis/NIR reflectance, air permeability, perspiration, light, wash fastnesses, and colorimetric values of each printed sample were evaluated. The presence of CB nanoparticles in printing formulations was found to cause significant decline in Near Infrared (NIR) reflectance of samples. The results showed that air permeability of samples printed containing CB nanoparticles are higher than samples printed with no CB particles. Absorbing phenomenon imposed by CB nanoparticles was fast against washing and perspiration, although printed samples indicated high to moderate light fastness. Furthermore, detectable change in visible appearance of the printed patterns was the main point of concern even at concentrations as low as 0.05 g/kg CB in printing formulation.

Colour Shift Photochromic Pigments in Colour Space CIE L*a*b*

ABSTRACT One of possibilities for protection of human body against acute and cumulative exposure to ultraviolet is the wearing of special protective clothes. Nevertheless on the other side the protective clothes have not the same barrier features against the UV light. The aim of present research work in LCAM on the Technical University of Liberec is research and development of original method of measurement by flexible textile based sensors reacting on the UVA part of electromagnetic radiation. In this article is publicized information about testing above mentioned sensors with weave structure and non-woven textiles. Results show that produced sensors shows sensitivity as to time of exposition so also to intensity of irradiation and their response characteristics is same as for classical luxmeters.

Effect of drawing ratio on difference in optical density and mechanical properties of mass colored photochromic polypropylene filaments

Abstract Photochromic textiles have been used in the sensible materials (sensor) in the smart textiles and esthetic materials in the fashion industry due to the color changing properties, which gives immense inspiration to prepare photochromic textile materials, in this regards we take more attention to prepare the mass dyed polypropylene filaments with photochromic pigments. Metallocene polypropylene filaments were doped by different concentration of photochromic pigment. In our experimental work, the optical and mechanical properties of these multifilaments depending on their drawing ratio were investigated. The photochromic pigment used was 5-Chloro-13-dihydro-133-trimethylspiro[2H-indole-23′-(3H)naphtha [2,1b](14)oxazine]. Regarding the optical properties, our investigation confirms the known effect of the primary reflectance on the depth of shade of colored multifilaments as shown by linear increase in difference in optical density with increasing ratio of fineness.

A Unique Device for Measurement of Photochromic Textiles

In this article, a unique concept for a device that conducts photochromic measurement in the reflectance mode together with the methodology described has been patented in the Czech Republic in the authors name. This unique device allows measurements of colorimetric and spectral characteristics of photochromic textiles as photochromic sensors and also as a fatigue tester for the control of color change stability. The measurement of colorimetric and spectral parameters in comparison together with the intensity of UV irradiation allows the dependence of color change on intensity of irradiation to determined, and a scale for individual visual observation to be developed, as well as the risks of UV irradiation to be evaluated.

In-situ development of highly photocatalytic multifunctional nanocomposites by ultrasonic acoustic method

Cotton-titania nanocomposites with multifunctional properties were synthesized through ultrasonic acoustic method (UAM). Ultrasonic irradiations were used as a potential tool to develop cotton-titania (CT) nanocomposites at low temperature in the presence of titanium tetrachloride and isopropanol. The synthesized samples were characterized by XRD, SEM, EDX and ICP-OES methods. Functional properties i.e. Ultraviolet protection factor (UPF), self-cleaning, washing durability, antimicrobial and tensile strength of the CT nanocomposites were evaluated by different methods. Central composite design and response surface methodology were employed to evaluate the effects of selected variables on responses. The results confirm the simultaneous formation and incorporation of anatase TiO2 with average crystallite size of 4nm on cotton fabric with excellent photocatalytic properties. The sustained self-cleaning efficiency of CT nanocomposites even after 30 home launderings indicates their excellent washing durability. Significant effects were obtained during statistical analysis for selected variables on the formation and incorporation of TiO2 nanoparticles (NPs) on cotton and photocatalytic properties of the CT nanocomposites.

A review of photochromism in textiles and its measurement

ABSTRACT Photochromism is a light-induced reversible change in colour defined as: ‘A reversible transformation in a chemical species between two forms having different absorption spectra brought about by photo-irradiation.’ This issue of Textile Progress provides a review of photochromism, the different methods for producing photochromic textiles, their properties, the measurement of kinetic colour changes, and their application in photochromic textiles. Photochromism can be utilised in a variety of textile products from everyday clothing to high-technology applications such as protective textiles, medical textiles, geo-textiles and sports textiles. Although photochromic materials have been used since 1960 to cut down the transmission of light through the lenses in sunglasses, there has been limited further development since that time due to technical difficulties not only in the application of photochromic colourants, but also with the measurement of kinetic colour-changing properties. Renewed interest in photochromic textiles has arisen due to improved commercial potential in particular for applications as photochromic nanofibres, in ‘smart’ textiles and in ‘smart’ clothing.

Photochromic Textiles and Measurement of Their Temperature Sensitivity

Our previous papers (Vikova & Vik, 2005) described a unique device, now patented in the Czech Republic in the authors name, for photochromic measurement in a reflectance mode together with a methodology. This device allows photochromic sensors to test the colorimetric and spectral characteristics of photochromic textiles, and also fatigue tests for control of colour change stability. This concept of colorimetric and spectral parameters also finds the dependence of colour change on the intensity of UV irradiation and temperature. In this paper, we would like to describe the dependence of colour change on temperature for the photochromic Photopia AQ Ink system (Blue, Purple and Yellow) produced by Matsui Shikiso Chemical Co.Ltd. It is known that the reversion of photochromic compounds from coloured to colourless is promoted thermally. The photochromic structure can achieve a lower level of saturated absorbance at higher temperatures when thermo reversible photochromic systems, such as spirooxazines and chr...

Colorimetric Properties of Photochromic Textiles

Photochromism is a chemical process in which a compound undergoes a reversible change between two states having separate absorption spectra, i.e. different colors. The change of color in one direction occurs under influence of electromagnetic radiation, usually UV light, and in the other direction by altering or removing the light source or alternatively by using thermal means. Based on photochromic pigment we developed simple textile sensor sensitive to UV light, which is usable for visual indication of intensity UV-A radiation. Main attention was given to colorimetric properties of photochromic textiles during decay phase of photochromic color change, such as saturation change and fatigue resistance.

Description of photochromic textile properties in selected color spaces

Research in color science includes studies on the spectral properties of light and the perception of color by the human eye and the brain. Color spaces allow the description of the position of a color by using three basic attributes, namely lightness, chroma and hue. Photochromic pigments used as a component of ultraviolet sensors can help to define color changes in time through the measurement of color differences in exposition and decay phases. The change of color can be evaluated in terms of the light source employed, reversion and the kinetics of photochromic effects. Commercial spectrometers are not suitable for this type of measurement. These instruments cannot measure the kinetics of exposure and the decay phase of photochromic materials. A unique spectrophotometer and a methodology for measuring colorimetric and spectral data of photochromic pigments in selected color spaces are presented. This work is the first step towards standardization of the measurement of color-changing materials containing functional dyestuffs, such as photochromic pigments.