Fluorescence associating polymers

Yekta, A., B. Xu, J. Duhamel, H. Adiwidjaja, and M. A. Wnnik. 1995. Fluorescence studies of associating polymers in water determination of the chain end aggregation number and a model for the association processMacromoleculeS8 956-966. 

The two linear poly(phenyleneethynylene) structures 88 and 89 <1995JA7017, 1995JA12593>, synthesized by a palladium-catalyzed cross-coupling reaction, act as very sensitive fluorescence chemosensors by forming in the presence of paraquat side-chain polypseudorotaxanes. Binding of the analyte causes a quenching of the fluorescence associated with the polymer backbone much more pronounced than that observed for a model monomeric species. 

Raman spectroscopy is useful for detecting metal-ligand and metal-metal bonds in molecular complexes, but it has not yet been successfully applied to polymer-supported catalysts. We believe that the low concentrations of the metal species and the fluorescence associated with the support are largely responsible for the lack of good spectra. Further work is expected to bring success with this method. 

Fluorescence and Light Scattering from Water-Soluble Hydrophobically Associating Polymers... 

Kumacheva E, Rharbi Y, Winnik MA, Guo L, Tam KC, Jenkins RD. Fluorescence studies of an alkalme swellable associative polymer in aqueous solution. Langmuir 1997 13 182-186. 

Based on an historical perspective, we begin our discussion with classical studies aimed at the compatibility and miscibihty of polymer chains with different chemical natures, because fluorescent studies have contributed significantly to understanding of the behavior of polymer blends. The middle part of the chapter is concerned with dilute polymer solutions whose properties reflect the behavior of isolated chains. Then the discussion is extended to concentrated solutions and polymer melts. The next part is related to the topic of associating polymers from a different viewpoint than that adopted in the other chapters of this book. Finally, we have added some comments on fluorescence studies of photo(electro)active polymers, because this field is a hot topic in contemporary polymer research. 

Prazeres TJV, Duhamel J, Olestm K, Shay G (2005) Correlations between the viscoelastic behavior of pyrene-labeled associative polymers and the associations of their fluorescent hydrophobes. J Phys Chem B 109 17406-17416... 

Fluorescence resonance energy transfer has also been used for ionic strength measurements.(95) Fluorescein labeled dextran (donor) and polyethyleneimine-Texas Red (acceptor) were placed behind a dialysis membrane. The polymer association is ionic strength dependent and the ratio of intensities (F o/Fw) was used as the measured parameter. Since both the donor and acceptor are fluorescent, this kind of sensor may allow expand the sensitive ionic strength range by shifts in observation wavelength, as was discussed for pH probe Carboxy SNAFL-2 (see Section 10.3). 

Our group [124] has used pyrene and pyrene labeled poly(acrylic acid) as a fluorescent probe to investigate the interaction between poly(acrylic acid) (PAA) and dodecyltrimethylammonium bromide (DTAB) in water. We have measured the Is /1 ratio of pyrene as a function of DTAB in the presence of 1 g/L PAA. A sharp decrease in polarity is found well below the CMC of DTAB (1.3 X 10 M, Fig. 17). The onset of this polymer-induced association is referred to as the critical aggregation concentration. The CAC has been measured at various pH and NaCl levels (Fig. 18). It was observed that the... 

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