Azobenzene-based polymers applications

Molecular glasses can be envisioned for the same applications as photoad-dressable polymers, but they have been studied far less extensively. It has been demonstrated that photoinduced birefringence can also be generated in thin films of azobenzene-based molecular glasses [54-58], Like homopolymers, they form SRGs in addition to gratings in the volume when illuminated with two interfering laser beams. 

This chapter discusses photochromic azobenzene polymers and photochromic molecules capable of undergoing photodimerization as materials for potential use in optical data storage applications. A brief introduction to photochromism, including recent examples of some photochromic systems, other than azobenzenes, based on variety of applications is presented at the outset. Thereafter, we shall focus on azobenzene photoaddressable polymers (PAPs) and [4 + 4]-photocycloaddition as materials for ultrahigh capacity optical data storage. 

Izumi and coworkers carried out similar preparations of conjugated polymers with azobenzenes in the main chain [212, 213]. Application of various palladium-catalyzed coupling methods such as the Suzuki coupling and the Heck reactions allowed formation of poly(p-phenylene)- and poly(phenyl vinylene)-based polymers ... 

Fonnation of surface relief grating (SRG) by irradiation of amorphous films of azobenzene-fiinctionalized acrylate, methacrylate, and qroxy-based polymers with two coherent laser beams has been a topic of current inteiest/ SRG, which is formed by the mass transport induced by the photoismnerization of the azobenzene chromqrhore, rrtay find potential applications fw oasable and rewritable hologr hic memoy, polarization discriminators, and waveguide couplors. 

With the emergence of photonics for telecommunication applications, there have been extensive activities related to the development of polymeric materials to this end. Several reviews are available on the synthesis and fabrication of polymer-based molecular wires and switches [67a-g]. In addition, a number of studies on azobenzene-containing... 

Photoresponsive molecularly imprinted membranes are based on the ability of cis-trans isomers of the polymers which have azobenzene in their molecular structure to undergo conformational rearrangement reaction, a fact which can be speculated for controlled release applications. Two such systems were developed for the controlled release of caffeine, the first by using 4-[(4-methacryloyloxy) phenylazo]-benzoic acid as a functional monomer and trimethylolpropane trimethacrylate [63], and the second by using 4-[(4-methacryloyloxy) phenylazo] benzenesulfonic add as a functional monomer and N,N - hexylenebismethacrylamide as a crosslinker [64]. In the case of the first system, it was foimd that by irradiation at 365 nm for 120 min, 58% of the active substance is released (in the same time period, by exposine to 440 nm, 94% of the caffeine quantity is released), while for the second system, by irradiation at 353 nm for 120 min, 84% of the caffeine quantity is released (94% by irradiation at 440 nm for 90 min). 

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