Micellar Properties of Sodium Sulfopropyl Alkyl Maleates in Aqueous SolutionA Time-Resolved Fluorescence Quenching Study

Abstract

The aggregation behavior of four sodium sulfopropyl alkyl maleates with alkyl chain carbon numbers 12, 14, 16, and 18 has been investigated in aqueous solution as a function of surfactant concentration, added sodium chloride concentration, and temperature by means of electrical conductivity and timeresolved fluorescence quenching (TRFQ). Critical micelle concentration and micelle ionization degree decrease upon increasing chain length, exhibiting the classical behavior for straight alkyl chain surfactants, whereas the Krafft temperature, T K, increases. The aggregation numbers have been found to decrease with increasing temperature between TK and 65 °C, with the magnitude of decrease becoming higher for longer hydrophobic chains. The surfactants show micellar growth with surfactant and salt concentration. Whereas the increase of the aggregation number N with ionic strength I is generally weak and follows in good approximation the power law relation N ∝ I β , with a unique exponent β = 0.13 below a surfactantdependent characteristic threshold ionic strength, I*, N steeply increases beyond I*. The values of N indicate that the micelles are probably spheroidal below I*. The micellar polydispersity is generally low for ionic strength I < I* and increases with I, in agreement with the theory of micellization.

Evolution of Aggregate Structure in Solutions of Anionic Monorhamnolipids: Experimental and Computational Results

“…To evaluate polydispersity further, the kinetics of the quenching rates are determined through fitting eq in the fluorescence lifetime measurements above. If significant polydispersity exists, then the A 3 fitting term in eq will vary with ⟨ Q ⟩ due to the loading of larger aggregates by quencher first. ,− Figure S10b shows the A 3 / A 3,min ratio as a function of ⟨ Q ⟩ along with the fraction of micelles ( f m = number of micelles/total number of aggregates) to generate a quantitative value for polydispersity. This plot shows a fraction of micelles of ∼1 across the entire mRL concentration range studied here, confirming negligible polydispersity.…”

Interactions between Quaternary Ammonium Surfactant Oligomers and Water-Soluble Modified Guars

“…The samples of fluorescent probes and quenchers (see below) used in the present investigation were the same as in previous studies (7)(8)(9)(10)(11)27). The ruthenium(II)-containing fluorescent probe (see below) was a gift from Pr.…”

“…They used the fluorescence probe/quencher pairs pyrene/cetylpyridinium chloride ( exc ϭ 335 nm; em ϭ 381 nm) or ruthenium[(bipyridyl) 2 (bipyridyl-2C 17 )] dichloride/9-methylanthracene ( exc ϭ 450 nm; em Ͼ 500 nm). The ligand bipyridyl-2C 17 bears two heptadecyl chains which anchor the probe to the hydrophobic microdomains (27 Equations [1] and [2] were fitted to the fluorescence decay curves of pyrene determined in the absence and in the presence of quencher, respectively (29 -33),…”

Alkyl melibioside and alkyl cellobioside surfactants: effect of sugar headgroup and alkyl chain length on performance

“…The quenching rate and viscosity of the intramicellar environment is also evaluated as an indicator of intramicellar reaction dynamics. However, k q as a viscosity indicator is convoluted with the size and shape of the micelle as well as the locations of the probe and quencher within the micelle [30][31]38. k q in SDS is 0.048 ns -1 ; therefore, the quenching reaction proceeds more slowly in micelles of longer chain alkyl cellobiosides and melibiosides.…”