Structural transition in micelles: novel insight into microenvironmental changes in polarity and dynamics

Chaudhuri, Arunima; Haldar, Sourav; Chattopadhyay, Amitabha

doi:10.1016/j.chemphyslip.2011.09.007

Cited by 25 publications

(10 citation statements)

References 88 publications

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“…A bathochromic shift in fluorescence emission caused by a shift in the excitation wavelength toward the red edge of the absorption band is termed as red edge excitation shift (REES). − REES has been used to study the microheterogeneity of membranes, micelles, polymers, and proteins, using different fluorescent probes. − ,− The phenomena of REES thus serves as an excellent tool to monitor the immediate environment around a fluorophore. In addition to REES, time-resolved anisotropy measurements have been widely used to probe the molecular dynamics of a fluorophore within a restricted environment. − Studies based on rotational dynamics are extremely helpful in understanding the nature of solvent friction around the fluorophore.…”

Section: Introductionmentioning

confidence: 99%

Microheterogeneity and Microviscosity of F127 Micelle: The Counter Effects of Urea and Temperature

Anand

Mukherjee

2014

Langmuir

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F127 is the most widely studied triblock copolymer and due to the presence of very long polypropylene oxide (PPO) and polyethylene oxide (PEO) groups, F127 micelle has different microenvironments clearly separated into core, corona, and peripheral regions. Urea has been known to have adverse effects on the micellar properties and causes demicellization and solvation; on the other hand, rise in temperature causes micellization and solvent evacuation from the core and corona regions. In the present study, we have investigated the microheterogeneity of the core, corona, and peripheral regions of the F127 micelle using red edge excitation shift (REES) at different temperatures and urea concentrations and correlated the effect of both on the micellar system. It was found that the temperature counteracts the effect of urea and also that the counteraction is more prominent in the core region with respect to corona, and the peripheral region is least affected. Also, the core and corona regions are very much heterogeneous, while the peripheral region is more of a homogeneous nature. Using time-resolved fluorescence anisotropy, we found that the microviscosity within the micelles vary in the order of core > corona > peripheral region, and urea has a general tendency to reduce the microviscosity, especially for core and corona regions. On the other hand, rise in temperature initially increases and then decreases the microviscosity throughout, and at elevated temperatures the effect of urea is being dominated by the effect of temperature, thereby establishing the counter effects of temperature and urea on the F127 micellar system.

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Section: Introductionmentioning

confidence: 99%

Microheterogeneity and Microviscosity of F127 Micelle: The Counter Effects of Urea and Temperature

Anand

Mukherjee

2014

Langmuir

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“…Hence, the electrostatic repulsion between the ionic headgroups of the surfactants decreases along with a concurrent increase in the hydrophobic interaction in the Stern layer, leading to the tighter packing facilitating more aggregation of the surfactant molecules. [12][13][14][15] Therefore, the hydrophobic cations of the hydrotrope (TBA + in this case) reside preferably in between the Stern layer and the diffused Gouy-Chapman layer. The above reasoning also seems justied on the basis of electrostatic interactions between the negatively charged headgroups of SDS micelles and the hydrotropic cations.…”

Section: Time-resolved Emission Spectramentioning

confidence: 99%

“…Charged micelles have been shown to be able to undergo structural changeover at a given temperature with increasing ionic strength of the medium or amphiphile concentration. 7,12,13 According to the Israelachvili model, 14 the screening of the repulsive interactions between the charged headgroups at a high electrolyte concentration assists the spherical micelle in acquiring an elongated rod-like shape. Such elongated micelles have been postulated to mimic the biological membrane more accurately as it possesses a more ordered orientation of the hydrocarbon chains.…”

Section: Introductionmentioning

confidence: 99%

Binding of a potential chloride channel blocker with an anionic surfactant and subsequent release in solution: effect of a hydrotropic solute in the post-micellar region

2014

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“…We use dynamic light scattering (DLS), Fourier transform infrared (FT-IR), and steady-state emission spectroscopy, trying to define where each type of alcohol is located, to extend the investigation to the formation of AOT RMs in ScCO 2 using the “best interacting” pentanol. Also, in the latter media, the red edge excitation shift , was used to confirm the formation of an organized system.…”

Section: Introductionmentioning

confidence: 99%

Is it Necessary for the Use of Fluorinated Compounds to Formulate Reverse Micelles in a Supercritical Fluid? Searching the Best Cosurfactant to Create “Green” AOT Reverse Micelle Media

et al. 2020

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Herein, we report the effect of employing two different alcohols, such as n-pentanol and 2,2,3,3,4,4,5,5-octafluoro pentanol (from now on F-pentanol), into 1,4-bis-2-ethylhexylsulfosuccinate (AOT) reverse micelles (RMs), to determine the interfacial activity and establish the best candidate to act as a cosurfactant in supercritical RMs. Dynamic light scattering (DLS), Fourier transform infrared (FT-IR), and fluorescence emission spectroscopy allowed us to determine and understand the behavior of alkanols in RMs. As a result, we found interesting displacements of alkanol molecules within the RMs, suggesting that the electrostatic interaction between SO3 – and Na+ weakens because of new interactions of n-pentanol with SO3 – through H-bonds, changing the curvature of the micellar interface. According to FT-IR and DLS studies, F-pentanol forms a RM polar core interacting through intermolecular H-bonds, suggesting no perturbations of the AOT RM interface. Hence, n-pentanol was selected as a cosurfactant to form supercritical RMs, which is confirmed by red edge excitation shift studies, using C343 as a molecular probe. Herein, we were able to create RMs under supercritical conditions without the presence of modified surfactants, fluorinated or multitailed compounds, which, to the best of our knowledge, was not shown before.

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Structural transition in micelles: novel insight into microenvironmental changes in polarity and dynamics

Cited by 25 publications

References 88 publications

Microheterogeneity and Microviscosity of F127 Micelle: The Counter Effects of Urea and Temperature

Microheterogeneity and Microviscosity of F127 Micelle: The Counter Effects of Urea and Temperature

Binding of a potential chloride channel blocker with an anionic surfactant and subsequent release in solution: effect of a hydrotropic solute in the post-micellar region

Is it Necessary for the Use of Fluorinated Compounds to Formulate Reverse Micelles in a Supercritical Fluid? Searching the Best Cosurfactant to Create “Green” AOT Reverse Micelle Media

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