Polarity profiles in reverse micelles of Triton X-100, as studied by spin probe and absorption probe techniques

Caragheorgheopol, Agneta; Bandula, Rodica; Căldăraru, Horia; Joela, Heikki

doi:10.1016/s0167-7322(97)00033-0

Cited by 17 publications

(37 citation statements)

References 20 publications

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“…It should have its proper location within the aggregate, and it should be sensitive enough to relevant changes in the system to be able to provide meaningful information. The polarity profile of the nonionic RM has been evidenced by absorption, fluorescence, and spin probe techniques [15,[20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

“…In the previous papers, the polarity variation in the core of RM of PEO [10] tert-octylphenyl ether (Triton X-100) in cyclohexane and 30:70 v/v benzene-n-hexane [21] and in the RM of Pluronic L62 (MW = 2600, corresponding to EO 6 PO 36 EO 6 ) and Pluronic L64 (MW = 2900, corresponding to EO 13 PO 30 EO 13 ) copolymers in o-xylene [22] has been reported in terms of Kosower's Z value, using different molecular probes and a new UV-vis absorption probe, 4-nitropyridine-N -oxide (NP). The relative radial positioning of all probes has been established [21,22].…”

Section: Introductionmentioning

confidence: 99%

“…The relative radial positioning of all probes has been established [21,22]. NP is one of the smallest organic optical probes that have been used for the investigation of such systems.…”

Section: Introductionmentioning

confidence: 99%

“…The nonionic surfactants of the alkyl ether and alkyl-aryl ether types may form micelles in nonpolar solvents, and water addition plays a very important role in micellization [15,[20][21][22][23][27][28][29]. The colloidal behavior of triblock copolymers of the PEO-PPO-PEO type (Pluronics) in nonaqueous media could be similar, but the information available in the literature is scarce.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Investigation of the micropolarity in reverse micelles of nonionic poly(ethylene oxide) surfactants using 4-nitropyridine-N-oxide as absorption probe

Bandula

Vasilescu

Lemmetyinen

2005

Journal of Colloid and Interface Science

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…The relative radial positioning of all probes has been established [21,22]. NP is one of the smallest organic optical probes that have been used for the investigation of such systems.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Investigation of the micropolarity in reverse micelles of nonionic poly(ethylene oxide) surfactants using 4-nitropyridine-N-oxide as absorption probe

Bandula

Vasilescu

Lemmetyinen

2005

Journal of Colloid and Interface Science

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“…The micropolarity variation in reverse micelles (RM) of nonionic PEO surfactants of the alkyl ether type (Brij 30), alkyl-aryl ethers (Triton X-100), and of Pluronics L62, L64, P123, and F127 copolymers has been studied using a UV-vis absorption probe, 4-nitropyridine-Noxide (NP) [29,34,35]. In our previous article, the micropolarity and order in the RM of L62 and L64 in o-xylene…”

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confidence: 99%

Imidazole derivatives as absorption probes for pluronics core-shell aggregates micropolarity investigation

Bandula

Vasilescu

2011

J Appl Spectrosc

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Their specific absorption parameters, sensitive to changes in micropolarity, were calibrated using the reference curves carried out in homogeneous tetraethyleneglycol/water mixtures. The probes were able to detect changes in the micelle micropolarity induced by hydration. Thus, with the help of calibration solutions, the effective local hydration of the polymeric chain sensed by the molecular probe solubilized in the guest aggregate was quantified and hypothetical relative locations of the probes in micelles have been proposed. The probes evidence differences in the micropolarity function of the structure (nature) and concentration of the Pluronic block copolymers.Introduction. The investigation of the self-organization of polymers in solutions is of fundamental and applicative interest. The triblock copolymers, poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO), Pluronics, are the focus of many researchers for their important industrial applications (detergency, cosmetics, emulsification, solubilization) and interesting aggregation properties in different solutions [1][2][3][4][5][6][7][8]. When mixed with water or oil, they form aggregates of various shapes and sizes [9][10][11]. Their preparation and properties have been reviewed in a series of publications and books [12][13][14][15]. In ternary (Pluoronic/oil/water) systems they present a rich structural polymorphism [16,17]. Many phase diagrams have been reported, and it has been established that the type of self-assembled microstructure depends on the block copolymer molecular weight, the PEO/PPO block ratio, the solvent type, and the polymer concentration and temperature [18][19][20][21].It is known that above a specific temperature (critical micellization temperature (CMT)) or concentration (critical micellization concentration (CMC)), PEO-PPO-PEO copolymers self-assemble in water as micelles where a hydrophobic core of PPO is surrounded by a hydrophilic shell (or corona) of hydrated PEO units. As described by a micellar model proposed by Pedersen and Gerstenberg [22], the dense spherical core is surrounded by non-interacting polymer chains. The size, shape, and kinetics of the aggregate formation are concentration-and temperature-dependent [9,10,23,24]. As the PPO core may contain some PEO and water, the interface between core and shell regions is not as distinct as in the case of the surfactant micelles in aqueous solution [9,10,22,23].Molecular probes (especially fluorescence probes) have been used by us to characterize nonionic poly(oxyethylenic) surfactant micelles [25][26][27][28][29] and polymeric micelles [30] and to study interactions of poly(oxyethylenic) surfactants with PEO [31], poly(acrylic acid) [32], and globular proteins [33]. The micropolarity variation in reverse micelles (RM) of nonionic PEO surfactants of the alkyl ether type (Brij 30), alkyl-aryl ethers (Triton X-100), and of Pluronics L62, L64, P123, and F127 copolymers has been studied using a UV-vis absorption probe, 4-nitropyridine-Noxide (NP) [29,34,35...

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FT-IR study of the properties of water in Triton N-42 inverse micelles

2007

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Polarity profiles in reverse micelles of Triton X-100, as studied by spin probe and absorption probe techniques

Cited by 17 publications

References 20 publications

Investigation of the micropolarity in reverse micelles of nonionic poly(ethylene oxide) surfactants using 4-nitropyridine-N-oxide as absorption probe

Investigation of the micropolarity in reverse micelles of nonionic poly(ethylene oxide) surfactants using 4-nitropyridine-N-oxide as absorption probe

Imidazole derivatives as absorption probes for pluronics core-shell aggregates micropolarity investigation

FT-IR study of the properties of water in Triton N-42 inverse micelles

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