Bending Moduli and Spontaneous Curvature. 2. Bilayers and Monolayers of Pure and Mixed Ionic Surfactants

Barneveld, P.A.; Hesselink, D.E.; Leermakers, F.A.M.; Lyklema, J.; Scheutjens, J.M.H.M.

doi:10.1021/la00016a021

Cited by 35 publications

(30 citation statements)

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“…However, the values of N a of the mixed micelles are slightly larger than those inferred from the values of single surfactants by linear interpolation. Indeed, some synergism in the formation of mixed micelles by surfactants with different alkyl chain is to be expected (Barneveld et al, 1994), as is also shown by the values of the cmcs for mixtures (table VI.1).…”

Section: Figure 23 the Differential Cross-section Of Sans From Solutsupporting

confidence: 55%

“…Accordingly, SANS detects an aggregate with lower axial ratio in the NaPal(D)/NaDod(H) system, where only NaDod contributes to the scattering. It is not quite clear why this situation should be energetically favourable, as the mean radius of curvature is smaller in end caps, and the bending energy of a mixed surfactant bilayer should be lower, the higher the fraction of short-chain surfactant (Barneveld et al, 1992(Barneveld et al, , 1994.…”

Section: Figure 23 the Differential Cross-section Of Sans From Solutmentioning

confidence: 99%

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Interactions between cationic starch and anionic surfactants

Merta¹,

Stenius²

1995

Colloid Polym Sci

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Section: Figure 23 the Differential Cross-section Of Sans From Solutsupporting

confidence: 55%

Section: Figure 23 the Differential Cross-section Of Sans From Solutmentioning

confidence: 99%

Interactions between cationic starch and anionic surfactants

Merta¹,

Stenius²

1995

Colloid Polym Sci

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“…It contains the electrostatic potential ⌿(z) that can be calculated, through Gauß' law, from the density profile, involving the dielectric permittivity profile, ⑀ r (z), and the charge ͑valence͒ profile, q(z)ϭ ͚ A e A A (z). 23,26,27 In this last equation A is the valence of segment A, A (z) the volume fraction of that segment at position z, and e the elementary charge. The potential in the reference state is taken to be zero.…”

Section: B the Partition Functionmentioning

confidence: 99%

Self-consistent-field modeling of complex molecules with united atom detail in inhomogeneous systems. Cyclic and branched foreign molecules in dimyristoylphosphatidylcholine membranes

Meijer

Leermakers

Lyklema

1999

The Journal of Chemical Physics

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We have developed a detailed self-consistent-field model for studying complex molecules in inhomogeneous systems, in which all the molecules are represented in a detailed united atom description. The theory is in the spirit of the approach developed by Scheutjens and co-workers for polymers at interfaces and self-assembly of surfactants and lipids into association colloids. It is applied to lipid membranes composed of dimyristoylphosphatidylcholine ͑DMPC͒. In particular, we looked at the incorporation of linear, branched, and cyclic molecules into the lipid bilayers being in the liquid phase. Detailed information on the properties of both the lipids and the additives is presented. For the classes of linear and branched alcohols and phenol derivatives we find good correspondence between calculated partition coefficients for DMPC membranes and experimental data on egg-yolk PC. The calculated partitioning of molecules of isomers, containing a benzene ring, two charged groups ͑one positive and one negative͒ and 16 hydrocarbon segments, into DMPC membranes showed variations of the partition coefficient by a factor of 10 depending on the molecular architecture. For zwitterionic additives we find that it is much more difficult to bring the positive charge into the membrane core than the negative one. This result can be rationalized from information on the electrostatic potential profile of the bare membrane, being positive in both the core and on the membrane surface but negative near the position of the phosphate groups. For several tetrahydroxy naftalenes we found that, although the partition coefficient is barely influenced, the average orientation and position of the molecule inside the membrane is strongly dependent on the distribution of the hydroxyl groups on the naphthalene rings. The orientation changes from one where the additive spans the membrane when the hydroxyls are positioned on ͑2,3,6,7͒ positions, to an orientation with the rings parallel to the membrane surface and located near the head grouphydrophobic core interface for the hydroxyls at the ͑1,3,5,7͒ positions. We propose that, when our model is used in combination with octanol/water partitioning data, a very accurate prediction is possible of the affinity of complex molecules for lipid membranes.

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“…Anderson et al 19 dominant role. 24,25 Early researchers 26,27 investigated the question, how a surfactant shields the unfavorable water-oil contact. Experience tells that the efficiency of a surfactant increases as the surfactant alkyl chain length is increased.…”

Section: Introductionmentioning

confidence: 99%

A small-angle neutron scattering study of nonionic surfactant molecules at the water–oil interface: Area per molecule, microemulsion domain size, and rigidity

Sottmann

Strey

Chen

1997

The Journal of Chemical Physics

180

212

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The small-angle neutron scattering (SANS) of bicontinuous microemulsions of 19 different water-n-alkane-CiEj (n-alkylpolyglycolether) systems has been measured. All scattering curves exhibit a broad scattering peak which permits determining the characteristic length scale ξ for bicontinuous structures at symmetric water and oil volume fractions, i.e., φ=0.5. Various random models predict ξ=aδφ(1−φ)/φc. We find that ξ is indeed inversely proportional to the surfactant volume fraction φc. Approximating the effective surfactant chain length δ by δ=νc/ac, where ac and νc are the area and the volume of the surfactant molecule, the numerical value for a is determined to be a=7.16, which is close to, but significantly different from those used in theoretical models. The head group area ac at the water–oil interface is obtained from the large q part of the scattering curves. It is found to be independent of i and k, the carbon numbers of the alkyl chain of the surfactant and of the alkane, respectively. However, it depends strongly, and nearly linearly, on the head group size j of the surfactant. Within experimental error it is described by ac=29.3+6.20j (Å2).

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Bending Moduli and Spontaneous Curvature. 2. Bilayers and Monolayers of Pure and Mixed Ionic Surfactants

Cited by 35 publications

References 0 publications

Interactions between cationic starch and anionic surfactants

Interactions between cationic starch and anionic surfactants

Self-consistent-field modeling of complex molecules with united atom detail in inhomogeneous systems. Cyclic and branched foreign molecules in dimyristoylphosphatidylcholine membranes

A small-angle neutron scattering study of nonionic surfactant molecules at the water–oil interface: Area per molecule, microemulsion domain size, and rigidity

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