Polymers sensory

Scheme 6.3S Sonogashira coupling for the synthesis of sensory polymers.

Kim TH, Swager TM (2003) A fluorescent self-amplifying wavelength-responsive sensory polymer for fluoride ions. Angew Chem Int Ed 42 4803 1806... 

A new transduction mechanism based on the aggregation of conjugated sensory polymers induced ions as described by Swager et al. [109]. This new system displays enhanced sensitivity because of energy migration processes and has a high selectivity for over Na" ions. 

Surface-enhanced Raman spectroscopy [252], a method based on an array of sensory polymers attached to fibre optics [253], has been used to determine down to 5 ppb and 100 ppb of 2,4-dinitrotoluene in soil. 

The versatility of the sensory amplification approach is expanded considerably by the ease with which it may be adapted to conductimetric detection methods. By way of example, consider sensory polymer 87, which is produced... 

The SA sensory polymer concept was first demonstrated in an analyte-induced quenching assay (Figure la) where the ligand to the receptor site was a quencher [4]. A key feature of the polymeric system was that the exciton migration caused greatly enhanced quenching relative to a chromophore bearing only one of the receptors. This is established by... 

Dinitrotoluene Chemical warfare agents Chloro-bispropyl ethers Custom vapor sampler Sensory polymers attached to fiber optics Flow injection amperometric enzyme biosensor Enantioselective GC-MS... 

Other ongoing efforts in our group currently examine the effects that large aromatic cores impart to important photophysical parameters in relation to the design of highly fluorescent sensory polymers. From these studies, we have... 

Uses. Cinnamyl alcohol and its esters, especially cinnamyl acetate, are widely employed in perfumery because of their excellent sensory and fixative properties. They are frequently used in blossom compositions such as lilac, jasmine, lily of the valley, hyacinth, and gardenia to impart balsamic and oriental notes to the fragrance. In addition, they ate utilized as modifiers in berry, nut, and spice flavor systems. The value of cinnamyl alcohol has also been mentioned in a variety of appHcations which include the production of photosensitive polymers (49), the creation of inks for multicolor printing (50), the formulation of animal repellent compositions (51), and the development of effective insect attractants (52). 

There have been a number of different synthetic approaches to substituted PTV derivatives proposed in the last decade. Almost all focus on the aromatic ring as the site for substitution. Some effort has been made to apply the traditional base-catalyzed dehydrohalogenation route to PTV and its substituted analogs. The methodology, however, is not as successful for PTV as it is for PPV and its derivatives because of the great tendency for the poly(u-chloro thiophene) precursor spontaneously to eliminate at room temperature. Swager and co-workers attempted this route to synthesize a PTV derivative substituted with a crown ether with potential applications as a sensory material (Scheme 1-26) [123]. The synthesis employs a Fager condensation [124] in its initial step to yield diol 78. Treatment with a ditosylate yields a crown ether-functionalized thiophene diester 79. This may be elaborated to dichloride 81, but pure material could not be isolated and the dichloride monomer had to be polymerized in situ. The polymer isolated... 

The types of spoilage caused by bacteria in fruits and vegetables are diverse they include sensory changes, degradation of compounds, and formation of new substances such as acids, volatile compounds, and polymers. For example, the bacteria produce a set of enzymes such as pectinases, cellulases, proteases, and others that causes maceration and softening of tissue. Off-flavor development is common in contaminated tissues, caused by volatile compounds produced by microflora (Jay 1992). 

The dominant attribute that has driven interest in fluorescent conjugated polymers (CPs) sensory materials is their ability to produce signal gain in response to interactions with analytes. The increased sensitivity (amplification) is derived from the ability of a conjugated polymer to serve as a highly efficient transport medium of electronic excitation. Analyte specificity in CP-based sensors results from the covalent or physical integration of receptors, imprinting, and/or the CP s overall electrostatic and chemical characteristics. The observed amplification is a... 

Yang NC, Chang S, Suh DH (2003) Synthesis and optically acid-sensory properties of novel polyoxadiazole derivatives. Polymer 44 2143-2148... 

Yang J-S, Swager TM (1998) Porous shape persistent fluorescent polymer films an approach to TNT sensory materials. J Am Chem Soc 120 5321-5322... 

Wang B, Wasielewski MR (1997) Design and synthesis of metal ion-recognition-induced conjugated polymers an approach to metal ion sensory materials. J Am Chem Soc 119 12-21... 

Thomas SW, Swager TM (2006) Trace hydrazine detection with fluorescent conjugated polymers a tum-on sensory mechanism. Adv Mater 18 1047-1050... 

Kim IK, Bunz UHF (2006) Modulating the sensory response of a conjugated polymer by proteins an agglutination assay for mercury ions in water. J Am Chem Soc 128 2818-2819... 

This concept is in essence a chromatographic effect similar to that observed in gas chromatography (GC), with the conjugated polymer film acting as the stationary phase. It is possible that like in GC and other candidate technologies for explosive detection, these responses could be empirically standardized for expected analytes of interest and sensory devices caHbrated to deconvolute temporal quenching signals to determine which analytes are present. This would further enhance the selectivity of what is already a very selective sensor for TNT and related compounds. 

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