Fluorescence Probes of Micellar Systems—An Overview

Singer, Lawrence A.

doi:10.1007/978-1-4613-3491-0_4

Cited by 14 publications

(1 citation statement)

References 64 publications

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“…Pyrene has been used since more than 50 years as fluorescent probe par excellence for microheterogeneous systems such as micelles [1][2][3][4][5][6][7][8][9][10][11][12][13], polymers [14][15][16], proteins [17][18][19], peptides [20] and biological membranes [18,[21][22][23]. The sensitivity of the pyrene fluorescence intensity to the solvent polarity is widely used for the determination of the cmc of micellar systems [3,12,13,[24][25][26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Fluorescence emission of pyrene in surfactant solutions

Piñeiro

Novo

Al‐Soufi

2015

Advances in Colloid and Interface Science

237

139

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The systematic description of the complex photophysical behaviour of pyrene in surfactant solutions in combination with a quantitative model for the surfactant concentrations reproduces with high accuracy the steady-state and the time resolved fluorescence intensity of pyrene in surfactant solutions near the cmc, both in the monomer and in the excimer emission bands. We present concise model equations that can be used for the analysis of the pyrene fluorescence intensity in order to estimate fundamental parameters of the pyrene-surfactant system, such as the binding equilibrium constant K of pyrene to a given surfactant micelle, the rate constant of excimer formation in micelles, and the equilibrium constant of pyrene-surfactant quenching. The values of the binding equilibrium constant K(TX100)=3300·10³ M⁻¹ and K(SDS)=190·10³ M⁻¹ for Triton X-100 (TX100) and SDS micelles, respectively, show that the partition of pyrene between bulk water and micelles cannot be ignored, even at relatively high surfactant concentrations above the cmc. We apply the model to the determination of the cmc from the pyrene fluorescence intensity, especially from the intensity ratio at two vibronic bands in the monomer emission or from the ratio of excimer to monomer emission intensity. We relate the finite width of the transition region below and above the cmc with the observed changes in the pyrene fluorescence in this region.

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Section: Introductionmentioning

confidence: 99%

Fluorescence emission of pyrene in surfactant solutions

Piñeiro

Novo

Al‐Soufi

2015

Advances in Colloid and Interface Science

237

139

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FT-EPR Study of Spin-correlated Radical Pairs Formed by Electron Transfer Quenching of Porphyrin Triplets in Micellar Solution

Weis

Willigen

1998

J. Porphyrins Phthalocyanines

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The spin-correlated radical pairs (SCRPs) formed by photoinduced electron transfer from zinc tetrakis(4-sulfonatophenyl)porphyrin ( ZnTPPS ) to quinones in micelles of the cationic surfactant cetyltrimethylammonium chloride ( CTAC ) were studied by means of Fourier transform EPR (FT-EPR). It is shown that variation of the power of the microwave pulse allows the separation of EPR signals arising from SCRPs and free radicals. The measured kinetics of radical formation can be accounted for in terms of a statistical model taking into account the non-uniform distribution of the solutes over the micelles. The rate constant of electron transfer quenching (kq) of the ZnTPPS triplet state by duroquinone (DQ) is found to be 1.05 × 106 s−1. The FT-EPR measurements gave information also on the kinetics of the homogeneous electron transfer reaction DQ − + DQ → DQ + DQ − in CTAC solution in which the DQ − anion radicals were generated by light-induced electron transfer from ZnTPPS . It is found that the dependence of the rate of this reaction on quinone concentration deviates from the linear relationship found in homogeneous solutions. A statistical model is proposed to account for the data. Based on this model, the rate constant of the self-exchange reaction (k ex ) is 4.1 × 106 s−1. From results obtained with duroquinone and benzoquinone as acceptors, it is concluded that ZnTPPS is located at the micelle/water interface.

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Photochemistry in Surfactant Solutions

Bünau¹,

Wolff²

1988

Advances in Photochemistry

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Fluorescence Probes of Micellar Systems—An Overview

Cited by 14 publications

References 64 publications

Fluorescence emission of pyrene in surfactant solutions

Fluorescence emission of pyrene in surfactant solutions

FT-EPR Study of Spin-correlated Radical Pairs Formed by Electron Transfer Quenching of Porphyrin Triplets in Micellar Solution

Photochemistry in Surfactant Solutions

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