The present invention provides a post-fabrication modification approach for the fabrication of colored and chromic materials and sensors using plasma surface modification to covalently bind the coloring agent to the substrate, thus avoiding leaching of the dye. Advantageously, in said methods, said coloring agent is a dye or pigment linked to a radical sensitive functional group, such as an alkenyl or alkynyl functional group, and is applied to the substrate prior to the gas plasma treatment. The methods envisaged herein are generic in nature, which allow the covalent immobilization of various dyes on different materials. The covalently coated materials after plasma surface modification, particularly the covalently coated chromic materials and sensors, can be used in many different applications, such as protective textile and wound dressing applications.

The present invention provides a post-fabrication modification approach for the fabrication of colored and chromic materials and sensors using plasma surface modification to covalently bind the coloring agent to the substrate, thus avoiding leaching of the dye. Advantageously, in said methods, said coloring agent is a dye or pigment linked to a radical sensitive functional group, such as an alkenyl or alkynyl functional group, and is applied to the substrate prior to the gas plasma treatment. The methods envisaged herein are generic in nature, which allow the covalent immobilization of various dyes on different materials. The covalently coated materials after plasma surface modification, particularly the covalently coated chromic materials and sensors, can be used in many different applications, such as protective textile and wound dressing applications.

The present invention provides a post-fabrication modification approach for the fabrication of colored and chromic materials and sensors using plasma surface modification to covalently bind the coloring agent to the substrate, thus avoiding leaching of the dye. Advantageously, in said methods, said coloring agent is a dye or pigment linked to a radical sensitive functional group, such as an alkenyl or alkynyl functional group, and is applied to the substrate prior to the gas plasma treatment. The methods envisaged herein are generic in nature, which allow the covalent immobilization of various dyes on different materials. The covalently coated materials after plasma surface modification, particularly the covalently coated chromic materials and sensors, can be used in many different applications, such as protective textile and wound dressing applications.

The present invention provides a post-fabrication modification approach for the fabrication of colored and chromic materials and sensors using plasma surface modification to covalently bind the coloring agent to the substrate, thus avoiding leaching of the dye. Advantageously, in said methods, said coloring agent is a dye or pigment linked to a radical sensitive functional group, such as an alkenyl or alkynyl functional group, and is applied to the substrate prior to the gas plasma treatment. The methods envisaged herein are generic in nature, which allow the covalent immobilization of various dyes on different materials. The covalently coated materials after plasma surface modification, particularly the covalently coated chromic materials and sensors, can be used in many different applications, such as protective textile and wound dressing applications.

Described herein are novel azo-benzene type chromophores. The chromophores are useful in photochromic compositions comprising a polymer matrix and a chromophore, wherein the chromophore is a novel azo-benzene type structure. The photochromic composition is photoresponsive upon irradiation by at least one wavelength of laser light across the visible light spectrum. Photochromic devices which comprise the novel azo-benzene type chromophore compound show significantly higher photoinduced birefringence, higher diffraction efficiency, and brighter images than devices that comprise well known azo-benzene chromophores. The photochromic composition may include a liquid crystal.

Described herein are novel azo-benzene type chromophores. The chromophores are useful in photochromic compositions comprising a polymer matrix and a chromophore, wherein the chromophore is a novel azo-benzene type structure. The photochromic composition is photoresponsive upon irradiation by at least one wavelength of laser light across the visible light spectrum. Photochromic devices which comprise the novel azo-benzene type chromophore compound show significantly higher photoinduced birefringence, higher diffraction efficiency, and brighter images than devices that comprise well known azo-benzene chromophores. The photochromic composition may include a liquid crystal.

A compound of formula (I) or (II) or (III): ##STR00001##
wherein R.sub.5, R.sub.6, R.sub.7, R.sub.8, R.sub.8 and R.sub.8 are as defined herein. This compound can be used in a composition for the dyeing of fibers.

Described herein are novel azo-benzene type chromophores. The chromophores are useful in photochromic compositions comprising a polymer matrix and a chromophore, wherein the chromophore is a novel azo-benzene type structure. The photochromic composition is photoresponsive upon irradiation by at least one wavelength of laser light across the visible light spectrum. Photochromic devices which comprise the novel azo-benzene type chromophore compound show significantly higher photoinduced birefringence, higher diffraction efficiency, and brighter images than devices that comprise well known azo-benzene chromophores. The photochromic composition may include a liquid crystal.