Halochromic materials

Chemichromism characterizes materials that are able to change their optical properties when their chemical environment changes. In particular, it includes ionochromism, halochromism and solvatochromism. 

Gels used as separation materials and polypeptides and which show halochromism will be described here. 

Photoswitchable materials molecular entities or supramolecular assemblies, which use light to toggle reversibly between distinct states of the system with markedly different properties [1, 2]. As a consequence of the changes produced at the molecular scale, a significant modification of some of the macroscopic properties of the material are induced. On this basis, many photochromic [3-5], fluorescence [6-8], chirality [9-11], and halochromic [12-14] switches have been reported during the past decades. 

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