Photochromic and Thermochromic Colorants in Textile Applications

Abstract

Commercial photochromic and thermochromic colorants that change rapidly and reversibly from colorless to colored state when activated by stimuli like ultraviolet irradiation, temperature or pH are well established class of colorants for manufacturing of niche products. Use of photochromic and thermochromic systems in applications like medical thermography, plastic strip thermometers, photochromic lenses, food packaging and nondestructive testing of engineered articles and electronic circuitry is well documented. However, in the last few years, the research on application of these systems on textiles has picked up significantly which has the potential to unlock commercially significant nascent high-tech applications. This review paper presents a summary of the chemistry, mechanism, application on textiles and evaluation procedure of performance, other technical features, current and potential application areas as well as challenges encountered in wider acceptance of photochromic and thermochromic colorants on textiles.

The study of colour fastness of commercial microencapsulated photoresponsive dye applied on cotton, cotton/polyester and polyester fabric using a pad‐dry‐cure process

“…The reaction is reversible, meaning that after removal of the illuminator, the photochromic dye reverts to its original (colourless) form. Photochromic dyes are applicable in a variety of areas, such as ophthalmics, information‐recording materials, dye laser and textile industry . Among these, ophthalmics represents the majority of consumed photochromic dyes, whilst the other above‐mentioned areas only represent a few per cent of the total value of the global business sales.…”

“…Among these, ophthalmics represents the majority of consumed photochromic dyes, whilst the other above‐mentioned areas only represent a few per cent of the total value of the global business sales. In textiles, photochromic dyes can be found in products with special colour effects (T‐shirts, handbags and caps), textured yarns for knitting, weaving and embroidery, UV‐light‐sensitive curtains and special photochromatic fabrics . Photochromic dyes can be applied on textiles using printing , exhaust dyeing , and pad dyeing .…”

“…Studies conducted so far have shown that polyester , polyamide and wool have been successfully dyed with photochromic dyes. Although the application of photochromic dyes onto textiles has been extensively studied , only a few patents and a study by Gorjance et al . were found regarding the application of photochromic microcapsules onto textiles by pad‐dry‐cure process.…”

Application of thermochromic colorants on textiles: temperature dependence of colorimetric properties

“…However, the wash fastness of such thermochromic systems needs to be improved further, as it may not match the stringent demands of modern‐day consumers. Another important aspect would be to improve the light fastness of the thermochromic pigments used in this study, as it was not found to be satisfactory .…”

Preparation of poly(methyl methacrylate‐co‐ethylene glycol dimethacrylate‐co‐glycidyl methacrylate) walled thermochromic microcapsules and their application to cotton fabrics

“…Thermochromic materials are intriguing substances, which exhibit reversibly color change depending on change of temperature . Because of their temperature sensing property, thermochromic materials have attracted considerable interest and are tested to determine their potential in many products and application areas like thermal indicators, optical storage devices, other luminescent switches, building coatings and cement, security printing plastic strip thermometers, food packaging, medical thermography, nondestructive testing of engineered articles, electronic circuitry, and pharmaceutical industry . Recently, textile industry has become one of the most interested sectors to thermochromic materials.…”