Photochromic materials can change their colour quickly and reversibly when exposed to light of certain wavelengths. These materials have recently been of great interest for intelligent and functional textile applications. In this study, two different photochromic dyes, including 1′,3′-dihydro-1′,3′,3′-trimethyl-6-nitro-spiro[2H-1-benzopyran-2,2′-(2H)-indole] and 1′,3′-dihydro-8-methoxy-1′,3′,3′-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2′-(2H)-indole], were microencapsulated by coacervation and in situ polymerization methods. Ethyl cellulose and melamine–urea–formaldehyde were used as polymers. The Fourier transform infrared spectroscopy, particle size and size distribution analysis, scanning electron microscopy, and ultraviolet spectrophotometry evaluations were utilized to characterize the structure, morphology, size distribution, and absorbance maxima of the photochromic microcapsules. The results indicated that photochromic microcapsules were in spherical shape, smooth, and homogeneous characteristics. These microcapsules were applied successfully onto cotton fabric using printing technique. Then, the activities of photochromic microcapsules on the fabrics were analysed by colour analysis under different light sources, fatigue resistance, washing, and rubbing fastness tests. After printing, the colours of the fabrics changed very quickly under different light sources. At the same time, these fabrics showed a reversible photochromic response and good fatigue resistance. Mechanical and physical properties of the fabrics such as thickness, air permeability and tensile and tear strength were also investigated. It can be concluded that photochromic microcapsules are well appropriate for brand protection and prevention of imitation in textile materials.

中文翻译：

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通过凝聚和原位聚合方法制备的光致变色微胶囊用于产品标记

当暴露在某些波长的光下时，光致变色材料可以快速且可逆地改变其颜色。这些材料最近在智能和功能性纺织品应用中引起了极大的兴趣。在这项研究中，两种不同的光致变色染料，包括1'，3'-dihydro-1'，3'，3'-三甲基-6-硝基-螺[2H-1-苯并吡喃-2,2'-（2H）-微囊化[吲哚]和1'，3'-二氢-8-甲氧基-1'，3'，3'-三甲基-6-硝基螺[2H-1-苯并吡喃-2,2'-（2H）-吲哚]通过凝聚和原位聚合方法。乙基纤维素和三聚氰胺-脲-甲醛用作聚合物。利用傅里叶变换红外光谱，粒度和粒度分布分析，扫描电子显微镜和紫外分光光度法评估来表征结构，形态，粒度分布，和光致变色微胶囊的吸光度最大值。结果表明，光致变色微胶囊具有球形，光滑且均匀的特征。使用印刷技术将这些微胶囊成功应用于棉织物上。然后，通过颜色分析在不同光源，耐疲劳性，耐水洗性和耐摩擦性测试下，分析了织物上光致变色微胶囊的活性。印刷后，在不同的光源下，织物的颜色变化非常快。同时，这些织物表现出可逆的光致变色响应和良好的抗疲劳性。还研究了织物的机械和物理性能，例如厚度，透气性以及拉伸强度和撕裂强度。