Nonlinear optical properties polymer synthesis

In the field of polymer chemistry the regio- and stereoselectivity of the Diels-Alder reaction is used for the concerted synthesis of structurally homogeneous double-stranded ladder polymers [39], which are useful materials with nonlinear optical properties and high electrical conductivity. It has turned out that the repeated Diels-Alder method is superior to an alternative two-step process, in which first an open chain precursor is formed followed by polymer ring closure as structural defects can occur [40]. 

Chiang, W. Thompson, M. E. Van Engen, D. Synthesis and Nonlinear Optical Properties of Inorganic Co-ordination Polymers. In Organic Materials for Nonlinear Optics II Hann, R. A., Bloor, D., Eds. Royal Society of Chemistry London, 1991 pp 210-216. 

The driving force in polymer synthesis is the search for new polymers with improved properties to replace other materials of construction. Polymers are lightweight and can be processed easily and economically into a wide range of shapes and forms. The major synthetic efforts at present are aimed at polymers with high temperature, liquid crystal, conducting, and nonlinear optical properties [Maier et al., 2001 Sillion, 1999]. There is an interrelationship between these efforts as will become apparent. 

The expectation that organometallics containing ligands with conjugated and delocalized tt systems will provide useful applications for the synthesis of new polyunsaturated organic substrates or serve as precursors to organometallic polymers displaying electronic conductivity and nonlinear optical properties has stimulated intense research efforts into their synthesis and properties. 

Osaheni and Jenekhe reported a synthesis of conjugated rigid-rod polymers and their NMR data. The conjugated rigid-rod polymers have interesting photoconductive, light-emitting and third-order nonlinear optical properties that have some potential for applications in optoelectronics and photonics. 

The synthesis of fullerene-containing polymers is noteworthy for several reasons. On the one hand, once Cgg is attached to a polymer, most of the fullerene properties are transferred to the polymer. Thus, for instance, electroactive and photoactive polymers or polymers with nonlinear optical properties can be prepared. On the other hand, hardly processible fullerenes embedded in highly soluble polymers may become more easily amenable to further treatments. The resulting materials might eventually be used for surface coating, photoconducting devices, or to create new molecular networks. 

Prior studies demonstrated that the properties of chemically synthesized polyaniline could be modified by the type of synthesis -electrochemical, chemical, or potential cycling methods (1-5). In addition the optical properties of polyaniline could be controlled by the substituents on the nitrogen or aromatic ring (6,7). Enzyme-catal5rzed polymer syntheses in organic solvents with different amounts of water were described in earlier publications (7-10), and nonlinear optical properties of some of these pol5miers were reported (11). This paper describes the horseradish peroxidase-catalyzed synthesis of polyaniline and the evaluation of its optical properties to determine differences, if any, between this polyaniline and those chemically synthesized. 

M. G. Murali, U. Dalimba, K. Sridharan, Synthesis, Characterization, and Nonlinear Optical Properties of Donor-acceptor Conjugated Polymers and Polymer/Ag Nanocomposites. /. Mater. Sci. 2012,47, 8022-8034. 

More recently, a soluble polymer (32) was prepared via reaction of l,l -ferrocenedimethanol with 4,4 -biphenyltetraamine in the presence of [RuCl2(P(C6115)3)3] (70). Approximately 20% of the iron centers were foimd to be in the Fe(III) state as a result of oxidation by ruthenium complexes formed during the polycondensation reaction. Wright and co-workers have reported the synthesis of ferrocene-based polymers possessing nonlinear optical properties (33) (71-73). These polymers were formed by polycondensation of a difunctionabzed ferrocene monomer (71). 

The brief presents a systematic study of synthesis of optically active polymers. It discusses in detail about the syntheses of three different types of optically active polymers from helical polymers, dendronized polymers and other types of polymeric compounds. The brief also explains the syntheses of optically active azoaromatic and carbazole containing azoaromatic polymers and copolymers optically active benzodithiophene and optically active porphyrin derivatives. The final chapter of the brief discusses different properties of optically active polymers such as nonlinear optical properties, chiroptical properties, vapochromic behavior, absorption and emission properties, fabrication and photochromic properties. The intrinsic details of different properties of optically active polymers will be useful for researchers and industry personnel, who are actively engaged in application oriented investigations. 

Optically active polymers play a very important role in our modem society. The specialities of optically active polymers are known with their various characteristics as occurred naturally in mimicry. The present review describes the monomers and synthesis of optically active polymers from its helicity, internal compounds nature, dendronization, copolymerization, side chromophoric groups, chiral, metal complex and stereo-specific behaviour. The various properties like nonlinear optical properties of azo-polymers, thermal analysis, chiroptical properties, vapochromic behaviour, absorption and emission properties, thermosensitivity, chiral separation, fabrication and photochromic property are explained in detail. This review is expected to be interesting and useful to the researchers and industry personnel who are actively engaged in research on optically active polymers for versatile applications. 

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