Microcapsule photochromic

Very much like the photochromic systems described previously in this chapter, organic thermochromic composites are prone to degradation caused by various external stimuli. To evaluate the extent of the damage and to determine the conditions under which the microcapsules may be used without the fear of lost functionality or complete loss of the colour-changing phenomenon, the following investigation was done. 

Interesting effects can be produced in textiles by using photochromic colorants. Because of stability problems in processing, these are often either incorporated into a polymer matrix inside textile fibres [76] or microcapsules containing the photochromic material are coated onto textile surfaces [77]. While products, such as T-shirts which change colour in sunlight, are available on the market, at present the development of this area is limited due to difficulties in obtaining cost-efficient, durable products [58]. 

PCMs are either in a solid or liquid state during their application. To prevent dissolution while in the liquid state, PCMs are enclosed in small plastic spheres with diameters of only a few micrometers. These microscopic spheres containing PCM are called PCM-microcapsules. Microscopic spheres that contain colour-changing polymers are called photochromic microcapsules or thermochromic microcapsules. 

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