Alternative UV Sensors Based on Color-Changeable Pigments

Abstract

Photochromism is a chemical process in which a compound undergoes a reversible change between two states having separate absorption spectra, i.e. different color [1]. In our previous work we have published some solutions of problems of measuring photochromic textile sample by standard commercial spectrophotometric systems [2]. Main problem with measurement of kinetic behavior of photochromic pigments by standard spectrophotometer is relatively long time period between individual measurements (5 s) and impossibility of measuring whole color change during exposure without interruption of illumination of sample during measurement. It means, standard commercial spectrophotometers enable off-line measurement of kinetic behavior during exposure period and quasi on-line measurement during reversion period. Based on this problem, it is only possible to obtain precise data during reversion-decay process and growth process (exposure) is affected by high variability of data. Following this knowledge, we developed original experimenttal system with short time scanning of color change of photochromic samples during growth and decay period of color change. In this study it is presented new view on the relationship between intensity of UV-A radiation and color change half-life t 1/2 . Via this relation, it is demonstrated the possibility of the flexible textile-based sensors construction in the area of the radiation intensity identification.

The determination of absorbance and scattering coefficients for photochromic composition with the application of the black and white background method

“…The additivity of the Kubelka-Munk function and also the absorbance and reflectance coefficients allow the elimination of the influence of used textile substrate and acrylic film and we can determine the change of absorbance (also the change of optical density DOD max ) in absorbance maximum for the individual pigments. [22][23][24][25][26] As documented in Table 3, the values of the absorbance maximums and the change of the optical density determined by the modified method of the black and white background are in good agreement with the values found from the literature sources measured by classical transmittance spectrophotometry for pure photochromic pigments without HALS, as is common for commercial photochromic pigments. 27,28 …”

Color Performance, Durability and Handle of Inkjet-Printed and UV-Cured Photochromic Textiles for Multi-Colored Applications

“…The kinetic model shown in equation (2) follows firstorder kinetics and is generally used to describe photochromic color behavior for both the coloration and decoloration reaction as seen in Figure 2 [19].…”

Photochromic Polypropylene Filaments: Impacts of Mechanical Properties on Kinetic Behaviour

“…Since it is non-polar in nature, with an aliphatic structure, high stereo-regularity and high textile materials to develop functional effects on a textile-based UV-sensor, camouflage, smart textiles and fashionable garments. Therefore we applied photochromic colorants to textiles through various techniques such as classical screen printing [20,21], mass coloration [11,12,18,22,23], digital printing [24][25][26], and melt-blown technology [27]. The main goal of this work was to find the relationship between the physical and mechanical properties and kinetic properties of mass colored PP filaments.…”