Hydrodynamic studies on benzethonium chloride micelles in dilute aqueous solution

Paradies, Henrich H.; Hinze, Ulrike; Thies, Michael

doi:10.1002/bbpc.19940980708

Cited by 10 publications

(7 citation statements)

References 18 publications

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“…The concentration of free surfactant, which is not used to stabilize the growing particles, ranges from 12 to 24 g/L, depending on the sample. The critical micelle concentration (cmc) for benzethonium chloride in aqueous solution has been studied by for example Paradies et al , and Emmerich . When neither salt nor buffer is added, the experimental value of the cmc varies between 0.9 and 1.5 g/L, depending on the method applied.…”

Section: Resultsmentioning

confidence: 99%

Characterization of Polyorganosiloxane Nanoparticles in Aqueous Dispersion by Asymmetrical Flow Field-Flow Fractionation

2001

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The advantages of asymmetrical flow field-flow fractionation (AF-FFF) for the characterization of aqueous dispersions of spherical polyorganosiloxane nanoparticles are discussed. With AF-FFF it was possible to obtain information about the synthesis, which is based on the hydrolysis and condensation of alkylalkoxysilanes in aqueous dispersion, and the average size of the spherical nanoparticles in the complex mixture in the presence of excess surfactant. The results are compared to measurements performed with dynamic light scattering (DLS). The size of the nanoparticles increases as a function of the amount of added monomer. Particles with radii between 2 and 50 nm are observed. If only the cross-linking monomer methyltrimethoxysilane (T) or a fixed monomer mixture of T and the chain-forming monomer diethoxydimethylsilane (D) is used, the increase in the radius shows a cube dependence on the volume of added monomer as expected. With AF-FFF it is also possible to obtain information on the role of the surfactant, which is needed to stabilize the particles. For spherical nanoparticles that are composed only of the trifunctional T or of a monomer mixture of T and D, it was found that the amount of surfactant needed to stabilize the growing particles is proportional to their surface. In the case of a more complex spherical core−shell architecture it was possible by AF-FFF analysis to obtain information about a secondary nucleation which may take place during the synthesis.

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Section: Resultsmentioning

confidence: 99%

Characterization of Polyorganosiloxane Nanoparticles in Aqueous Dispersion by Asymmetrical Flow Field-Flow Fractionation

2001

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“…The values obtained supplement previously determined data 6 and are useful for comparison with ternary mutual diffusion coefficients that were determined conductometrically for AOH in this study. The static and inelastic light-scattering (QELS) experiments were conducted with an ALV-LSE-3000 goniometer (Langen, Germany) consisting of LSE/80 light-scattering electronics, a PM-20 multiplier, and a monitor unit . Unpolarized laser light (NEC-Laser, 50 mW Ne) of 632.8 nm was used.…”

Section: Methodsmentioning

confidence: 99%

“…The static and inelastic light-scattering (QELS) experiments were conducted with an ALV-LSE-3000 goniometer (Langen, Germany) consisting of LSE/80 light-scattering electronics, a PM-20 multiplier, and a monitor unit. 16 Unpolarized laser light (NEC-Laser, 50 mW Ne) of 632.8 nm was used. An ALV-3000 multibit, multi-τ correlator was operated with 25 simultaneous sampling times covering where k B T is the thermal energy, f 0 is the friction factor at infinite dilution, H(K) is the hydrodynamic interaction parameter, and S(K) is the solution structure factor.…”

Section: Methodsmentioning

confidence: 99%

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Multicomponent Diffusion of Distearyldimethylammonium Polyelectrolyte Solutions in the Presence of Salt: Coupled Transport of Sodium Chloride

Thies¹,

Clancy²,

Paradies³

1996

J. Phys. Chem.

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A sensitive conductance method has been used to determine binary and ternary diffusion coefficients of distearyldimethylammonium chloride, bromide, and hydroxide (DSDMACl, DSDMABr, and DSDMAOH) in aqueous solutions in the absence and presence of salt. Experiments were conducted above and below the critical micelle concentration (CMC) at 25°C, and the concentration of salt, when present, was 0.015 M NaX (X ) Cl, OH, Br). The experiments reveal that diffusion of DSDMA chloride, bromide, and especially hydroxide induces concurrent flow of NaCl, NaBr, and NaOH, respectively. Also, diffusion of DSDMAX in the presence of NaCl drives countertransport of DSDMACl or DSDMAOH. At pH 7.5 and an ionic strength of 0.015 M, each mole of diffusing DSDMACl (N agg ) 72, R ) 0.15) cotransports 9.0 mol of NaCl. However, coupled flow of NaCl decreases as the solution pH approaches 5.2 and is almost zero at pH 4.5. The corresponding value for diffusing DSDMAOH at pH 7.5 is about 120 mol of NaCl. At pH 6.5 only 10 mol of NaCl are cotransported, and the value is almost zero at pH 5.5. However, at pH 4.5, diffusing DSDMAOH generates a counterflow of NaCl due to bound protons and a release of H 2 O (DSDMAOH + H + T DSDMA + + H 2 O), yielding a net positive charge; hence, the D 21 value is negative. The cross-diffusion coefficient D 21 of diffusing DSDMACl in the presence of 0.015 M (0.095-0.009) NaOH and 0.015 M NaCl yields a flux density of NaOH and NaCl, which is generated by the DSDMAX (X ) Cl + OH) gradient. A similar cross-diffusion coefficient, D 21 , is revealed when DSDMAOH, is used, instead of DSDMACl, in the presence of 0.015 M NaCl through induced coupled transport of salt. The coupled transport of NaCl or of NaCl and NaOH is primarily driven by the diffusion-induced electric field along the DSDMAOH and DSDMACl concentration gradients. For the DSDMAOH system, the direction and magnitude of the coupled flow of either NaCl or NaOH can be explained through the ionic mobility of DSDMA + and OH -, in addition to the charge and degree of dissociation (N agg ) 6400, R ) 0.33-0.35) at 25°C. The tracer and mutual diffusion coefficients for the DSDMAX system were compared with those from light-scattering measurements of polyelectrolyte solutions of DSDMAX.

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“…7 The reported biological activities account for Bzth-Cl concentrations in the µM range, that are much lower than the critical micelle concertation (CMC) of Bzth-Cl of 0.54 mM and 1.84 mM as determined recently by intrinsic fluorescence spectroscopy in water, 8 or of 0.84 mM to 1.15 mM in 0.01 M Tris-HCl buffer, pH 7.5 (293 K) determined by light scattering, surface tension and electric conductivity measurements. [9][10][11] The inhibition of the acetylcholinesterase and the cholinesterase, respectively, is completely inhibited at K i ∼ 0.15 mM. 12 Single or double chained cationic nitrogen containing lipids reveal antiviral activities at the 0.1 µM level 13 e.g.…”

Section: Introductionmentioning

confidence: 99%

Influence of the anions on the N-cationic benzethonium salts in the solid state and solution: Chloride, bromide, hydroxide and citrate hydrates

Paradies

Reichelt

2016

AIP Advances

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The crystal structures of the hydrated cationic surfactant benzethonium (Bzth) chloride, bromide, hydroxide, and citrate have been determined by X-ray diffraction analysis and compared with their structures in solution well above their critical micelle concentration. The differences in the nature of the various anions of the four Bzth-X materials lead to unique anion environments and 3-D molecular arrangements. The water molecule in the monoclinic Bzth-Cl or Bzth-Br forms is hydrogen bonded to the halides and particularly to the hydrogens of the methoxy groups of the Bzth moiety notwithstanding the weak Brønsted acidity of the methoxy hydrogens. The citrate strongly interacts with the hydrogens of the methoxy group forming an embedded anionic spherical cluster of a radius of 2.6 Å. The Bzth-OH crystallizes in a hexagonal lattice with two water molecules and reveals free water molecules forming hydrogen bonded channels through the Bzth-OH crystal along the c-axis. The distances between the cationic nitrogen and the halides are 4.04 Å and 4.20 Å, significantly longer than expected for typical van der Waals distances of 3.30 Å. The structures show weakly interacting, alternating apolar and polar layers, which run parallel to the crystallographic a-b planes or a-c planes. The Bzth-X salts were also examined in aqueous solution containing 20% (v/v) ethanol and 1.0 % (v/v) glycerol well above their critical micelle concentration by small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS). The [1,1,1] planes for the Bzth Cl or Br, the [0,0,2] and [1,1,0] planes for the Bzth-citrate, the [2,-1,0] planes and the [0,0,1] planes for the Bzth-OH found in the crystalline phase were also present in the solution phase, accordingly, the preservation of these phases are a strong indication of periodicity in the solution phase.

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Hydrodynamic studies on benzethonium chloride micelles in dilute aqueous solution

Cited by 10 publications

References 18 publications

Characterization of Polyorganosiloxane Nanoparticles in Aqueous Dispersion by Asymmetrical Flow Field-Flow Fractionation

Characterization of Polyorganosiloxane Nanoparticles in Aqueous Dispersion by Asymmetrical Flow Field-Flow Fractionation

Multicomponent Diffusion of Distearyldimethylammonium Polyelectrolyte Solutions in the Presence of Salt: Coupled Transport of Sodium Chloride

Influence of the anions on the N-cationic benzethonium salts in the solid state and solution: Chloride, bromide, hydroxide and citrate hydrates

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