Aqueous Solution Properties of Disulfide Linked Gemini and Cleaved Monomeric Thiol Surfactants

Abstract

Monomeric thiol surfactants, [C n H 2n+1 N(CH 3 ) 2 CH 2 CH 2 SH]Br, were produced by the cleavage of gemini surfactant containing a disulfide bond in the spacer chain, [C n H 2n+1 N(CH 3 ) 2 CH 2 CH 2 SSCH 2 CH 2 N(CH 3 ) 2 C n H 2n+1 ]2Br. The disulfide bond was completely reduced by the addition of four times moles of dithiothreitol in water at room temperature. The critical micelle concentrations of monomeric surfactants were significantly increased in comparison with original gemini surfactants. The monomeric thiol surfactants were stable in the presence of dithiothreitol, whereas they returned gradually to their original gemini surfactants within several days due to air oxidation in water without dithiothreitol. The micelle formation induced by the disulfide linkage formation was suggested by the fluorescence intensity ratio of pyrene. The time course of decrease in thiol concentration associated with the recovery of gemini surfactants was confirmed by the absorption spectra utilizing the reactions with 4,4'-dithiopyridine.

Aggregation Behavior of Disulfide Linked Gemini Surfactants Compared to that of Double Tailed Surfactants

“…Thus the conductivity of 5 mM 2C 12 SS micelle solution will increase with increasing of monomeric C 12 SH concentration by the cleavage of disulfide bonds. In addition, the cyclic disulfide is not surface active, and is not ionic conducting species 9 . Figure 6 a shows the timecourse of conductivity for 5 mM 2C 12 SS with addition of 5 mM DTT in comparison with 5 mM 2C 10 11SS.…”

“…We have reported that the transformation from the gemini to monomeric surfactants was performed by the addition of dithiothreitol, which is commonly used to cleave the disulfide bond into free thiols 9 . Subsequently, the produced thiol surfactants can be expected to return to the original geminis by the formation of disulfide when exposed to air.…”

Micelle–Vesicle Transition by Cleavage of Disulfide Spacer Chain for Gemini Surfactant in Didodecyldimethylammonium Chloride Aqueous Solutions

“…The production of single-tailed surfactant by cleavage of disulfide linked gemini surfactants with the addition of dithiothreitol DTT has been reported in our previous work 9,10 , shedding light on single-tailed thiol surfactants which influence the vesicular region in comparison with conventional single-tailed or gemini surfactants 11 . The critical micelle concentration CMC was determined using conduc-tivity and pyrene fluorescence probe methods.…”

“…C 12 H 25 N CH 3 3 Cl DTAC and didodecyldimethylammonium chloride DDAC were purified by repeated recrystallization from acetone. C 12 H 25 N CH 3 2 CH 2 6 N CH 3 2 C 12 H 25 2Cl C 12 -6-C 12 were synthesized using a procedure similar to the one reported previously 9 . DTT Wako Pure Chemical Industries, Ltd. was used as received.…”

Aggregation and pH Responsive Behavior of Thioester Surfactants and Formation of Disulfide Linkages in Aqueous Solutions

“…pyrene is released during the reduction of gemini micelles into monomeric thiol surfactants upon the addition of dithiothreitol DTT , which is commonly used to cleave the disulfide bond into free thiols 8 . Moreover, the produced thiol surfactants return to the original disulfide-linked gemini form in aerated solution.…”