Light sensitive polymers structure

The aqua ion as a ligand is discussed in section 4.5. Silver forms a range of light-sensitive, insoluble carboxylates that find application in the synthesis of, for example, alkyl halides and esters. The benzoate, trifluoroacetate and perfluorobutyrate have dimeric structures others are polymers (Figure 4.6). 

Experimental and theoretical results are presented for four nonlinear electrooptic and dielectric effects, as they pertain to flexible polymers. They are the Kerr effect, electric field induced light scattering, dielectric saturation and electric field induced second harmonic generation. We show the relationship between the dipole moment, polarizability, hyperpolarizability, the conformation of the polymer and these electrooptic and dielectric effects. We find that these effects are very sensitive to the details of polymer structure such as the rotational isomeric states, tacticity, and in the case of a copolymer, the comonomer composition. 

Limited structural information is available for silver(I) carboxylates, despite their extensive use as catalysts in the manufacture of urethane polymers. This is in part due to their frequent insoluble and light-sensitive nature making chemical characterization of the complexes difficult. Dimeric structures have been reported for the perfluorobutyrate249 and trifluoroacetate complexes.250 In each case two-fold symmetry was crystallographically imposed. The Ag—O bond lengths were 223-224 pm, and in the more accurate determination of the trifluoroacetate, the Ag—Ag separation was found to be 297 pm. A dimeric structure was also found for the silver(I) complex of 3-hydroxy-4-phenyl-2,2,3-trimethylhexane carboxylate.251 In the asymmetric crystal unit the Ag---Ag separations were 277.8 and 283.4 pm. 

From the same class of light sensitive and heat resistant polymers, poly[4,4 -hexafluoro-isopropylidene)-diphthalic anhydride-a/f-acridine yellow G], HCI is given as another example. The structure of this polymer is shown below ... 

Recently, we explored strategies for binding spiropyran moieties to structured brushes grafted from ETFE and Teflon (PTFE) surfaces in order to obtain light-sensitive structured polymer surfaces [18]. We focused on post-polymerization modification of grafted brush structures because this strategy increases the flexibility with respect to the optimization of the concentration of spiropyran moieties in the brushes. Moreover, the tedious synthesis and purification steps of spiropyran—monomer conjugates are circumvented. 

However, it is often difficult to remove trace amounts of copper adsorbed by the polymer. The synthesis, characterization, and some properties of the light-sensitive DA-containing polymers, 1 and 2, enq>loyed for this study have been reported previously by the authors 15J6J7J8J9). A few novel aromatic DA-containing, ligjht-insensitive polyesters, 3 and 4, were also synthesized. Their structures are shown in Chart 1. 

Moreover, some investigations have dealt with the combination of the photonic properties and the ordered porous structure for light-harvesting or emitting. In both cases, light-sensitive honeycomb films based on semi-conductive NPs or conjugated polymers were used to improve the opto-electronic properties of organic thin-film devices [126, 161, 174,176, 190-192]. 

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