Photoresponsive Systems. I. Photochromic Macromolecules

Abstract

Azo dyes bearing acrylamide groups were synthesized and copolymerized with acrylic and methacrylic acids to yield photochromic polyelectrolytes. The optical behavior of the isomerizing side chains was qualitatively studied, especially the cis + trans isomerization process, and compared with that of corresponding alkylamide dyes (copolymerized monomer dye models), which are also photochromic and moderately soluble in water. Preliminary comparison of adsorption bound dyes was made. The geometry of the various dyes can be switched a t will by irradiation, but the relaxation processes vary with environment of the dye, so that three distinct types of dye are defined: free dyes, adsorption bound dyes, and covalently bound (or tethered) dyes. All these behave reversibly and react with nucleophilic catalysts. In the case of the tethered dyes, irradiation response and dark relaxation behavior are linked to the charge and conformation of the copolyelectrolyte.

Polyelectrolyte Solutions: Phenomena and Interpretation

“…These phenomena were clearly due to the repulsion of the OH ion from the polymer, which was decreased when salt was added. A similar effect was reported for a copolymer of N-azobenzeneacrylamide with acrylic or methacrylic acid, where the OH catalyzed cis-trans isomerization of the azobenzene moiety was inhibited (27).…”

Azo Polymers

“…The synthesis of polymers containing side-chain azo groups has been achieved by modification of a preformed polymer (95)(96)(97)(98)(99)(100)(101), or copolymerization of a monomer having additional azo functionality with a simple monomer such as styrene or methyl methacrylate (102)(103)(104)(105)(106)(107)(108)(109)(110)(111)(112)(113). Many examples of the first method are given in the literature; the modification of cellulose is typical (95).…”

“…It is not surprising that many attempts have been made to copolymerize azo-containing monomers (93,(102)(103)(104)(105)(106)(107)(108)(109)(110)(111)(112). Examples of azo-containing monomers which have been synthesized and polymerized are shown below.…”

“…However, the azo function may not be inert to radicals (102,108). Furthermore, it is important to know the photochromic properties of the particular azo group (108,109).…”

Polyureas: Synthesis, Characterization and Dyeing Application in Nylon and Polyester

“…They are soluble in the medium in which they are applied or in the substrate with which they form a composite. Their utilization has been possible because of certain essential dye properties such as fast leveling on fiber, fastness to light and wet treatment, low sublimation rate and very good thermal and chemical resistance [1][2][3] , one of the dye moiety i.e., cryosidine type, which have two amino functional groups. This dye can produce polyurea with diisocyanate.…”