Alkanediyl-.alpha.,.omega.-bis(dimethylalkylammonium bromide) surfactants. 3. Behavior at the air-water interface

Diester-containing Zwitterionic Gemini Surfactants with Different Spacer and Its Impact on Micellization Properties and Viscosity of Aqueous Micellar Solution

“…Unlike the synthesized bispyridinium gemini surfactants reported by Fisicaro et al, amin values of these surfactants increases with increasing spacer length 28,29 . Such a pattern of increase in a min values with increasing spacer length was also observed by Menger et al 22 for linear chain length zwitterionic gemini analogues and Zana et al 30 for gemini quaternary ammonium surfactants. The prime factor responsible for the deviation of a min values with spacer is the balance attractive interactions between tails and repulsive interactions between heads suggested by a theoretical model 31,32 .…”

“…As shown in Table 2, the value of ΔG ads is more negative than ΔG mic which is evident of the adsorption tendency of an individual surfactant being greater than the micellization at air/water interface is attributed to the adsorption deals with thermodynamic characteristics of surfactant molecule at interface. In other words, the hydrophobicity of the molecules projects them towards the air/water interface and micellization took place after surface adsorption 30 . In our study, the smaller energy gap between ΔG mic and ΔG ads in the individual zwitterionic gemini surfactant indicated greater tendency to aggregate in solution rather than adsorbing at the air/water interface.…”

Physicochemical and toxicological properties of novel amino acid-based amphiphiles and their spontaneously formed catanionic vesicles

“…In the case of the monovalent cationic surfactants n was taken as 2 since the surface tension was measured in neat water [46] while it was taken as 1 for the two anionic surfactants due to the presence of NaOH 0.0100 mol dm −3 in solution [47]. Table 1 lists the interfacial parameters determined for the studied surfactants.…”

“…In addition, the existence of groups where intermolecular hydrogen bonding can occur, namely the N-H and C O groups, can further enhance the surface adsorption [24,[48][49][50]. For instance, comparing this surfactant with a bis(quaternary ammonium) gemini surfactant with four CH 2 spacer groups [46], it can be seen that the lysine derivative attains a much lower surface tension at the cmc (12-4-12: 39.8 mN m −1 ; 12Lys12: 27.1 mN m −1 ). With respect to the interfacial molecular areas in Table 1, they also follow a trend coherent with the previous considerations, with the largest and smallest areas observed for the Tyr-and Lys-amphiphiles, respectively.…”

<i>In Vitro</i> Evaluation of the Biocompatibility of Newly Synthesized Bis-Quaternary Ammonium Compounds with Spacer Structures Derived from Pentaerythritol or Hydroquinone

“…It should be noted that MBCs of 3PHBO-8 and 3HHDMP-8 against all tested bacteria were more than 100 mg/L, and therefore the exact MBC was not determined. The spacer structure crosslinking two cationic pyridinium rings in bis-QAC is known to affect antimicrobial activity Alami et al, 1993;Ohkura et al, 2005;Shirai et al, 2006 . For example, the antibacterial activity of bis-QACs with a longer methylene spacer is less likely to be affected by the length of the alkyl chain, though the activities of bis-QACs that have a short methylene spacer vary considerably depending on the length of the alkyl chain.…”