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A dye is a colored substance that chemically bonds to the material to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution and may require a mordant to improve the fastness of the dye on the fiber. [2]
The dye(s) are usually seeded everywhere in the flow and differential quenching of their fluorescence by analytes is directly observed. Fluorescence-based assays for screening toxic chemicals. The optical assays consist of a mixture of environment-sensitive fluorescent dyes and human skin cells that generate fluorescence spectra patterns. [ 88 ]
Dexter (also known as Dexter exchange or collisional energy transfer, colloquially known as Dexter Energy Transfer) is another dynamic quenching mechanism. [12] Dexter electron transfer is a short-range phenomenon that falls off exponentially with distance (proportional to e −kR where k is a constant that depends on the inverse of the van der Waals radius of the atom [citation needed]) and ...
Broadly, dyes are soluble and become fixed to a substrate via impregnation, while pigments are insoluble and require a binding agent to adhere to a substrate. Dyes, therefore, must have an affinity for the substance they are intended to color. [4] Chemically speaking, pigments can be organic or inorganic, while dyes are only organic.
The UV-vis spectrum for a compound that appears orange in Dimethylformamide. All atoms and molecules are capable of absorbing and releasing energy in the form of photons, accompanied by a change of quantum state.
Reactive dyes have good fastness properties owing to the covalent bonding that occurs during dyeing. Reactive dyeing is the most important method for coloring cellulose fibers . Reactive dyes can also be applied on wool and nylon ; in the latter case they are applied under weakly acidic conditions.
This is a list of dyes with Colour Index International generic names and numbers and CAS Registry numbers. This list is incomplete; you can help by adding missing items.
Thermochromic dyes are based on mixtures of leuco dyes with other suitable chemicals, displaying a color change (usually between the colorless leuco form and the colored form) that depends upon temperature. The dyes are rarely applied on materials directly; they are usually in the form of microcapsules with the mixture