Gemini-Tenside

Menger, Fredric M.; Keiper, Jason S.

doi:10.1002/1521-3757(20000602)112:11<1980::aid-ange1980>3.0.co;2-d

Cited by 62 publications

(22 citation statements)

References 73 publications

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“…Aiming at the high self‐assembly efficiency of biomolecules such as DNA or proteins, synthetic bio‐inspired capping agents have gained popularity as surface templates in the formation of self‐assembled colloidal supercrystals over micrometer length scales . Among them, gemini surfactants comprising two hydrophobic tails and two hydrophilic headgroups linked by a molecular spacer, have proven excellent stabilizers and binders in nanoparticle synthesis and self‐assembly, since they may mimic the bilayer formation of phospholipids in biomembranes . In fact, we have recently investigated the structural role of gemini surfactants on the controlled synthesis of monodisperse AuNRs that self‐assemble into ordered, standing 2D and 3D superlattices by simple drop casting .…”

Section: Average Widths (±2 μM) Of the Supercrystal Intermediate Layementioning

confidence: 99%

Self‐Assembly of Au@Ag Nanorods Mediated by Gemini Surfactants for Highly Efficient SERS‐Active Supercrystals

Gómez‐Graña

Pérez‐Juste

Alvarez-Puebla³

et al. 2013

Advanced Optical Materials

102

101

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A 3D super lens composed of fractal left-handed materials is realized by H.-X. Xu, T. J. Cui, and co-workers. By incorporating four interdigital capacitors in the Sierpinski fractal curves of the second iteration order, the left-handed transmission-line material facilitates an electrically small dimension and a broadband negative magnetic response. Based on such metamaterials, a planar slab super lens is designed and fabricated on page 495. Both numerical and experimental results illustrate that the superlens exhibits excellent impedance matching to free space and significantly improves the imaging resolution. NanorodsA silver coating takes the lead in the SERS enhancement contest for nanorod supercrystals. On page 477, A. Guerrero-Martínez, L. M. Liz-Marzán, and co-workers determine that supercrystals based on standing core-shell gold-silver nanorods stabilized by gemini surfactants are the SERS champions, knocking out their gold nanorod supercrystal counterparts. After a tough competition, silver substrates show a perfect combination of high optical activity and large homogeneous sensing area that will be difficult to defeat. Chiral StructuresAsymmetric transmissions of circularly polarized optical waves can be achieved when the waves are incident normal to planar chiral structures, provided that the structures are anisotropic and lossy. In order to clarify how the factor of loss affects the asymmetric transmission, Z. Li, M. Gokkavas, and E. Ozbay studied a typical planar chiral structure by using an optical lumped element model. On page 482, they found that the anisotropy of loss, instead of the whole loss, plays a crucial role for achieving asymmetric transmission.Entering its second decade as a top tier materials science journal, Advanced Functional Materials reports breakthrough research in all aspects of materials science, including nanotechnology, chemistry, physics, and biology.The fabrication of supercrystals of standing core-shell gold-silver nanorods stabilized by gemini surfactants provides SERS substrates with high optical activity, large homogenous sensing areas, and the potential to maximize the SERS signal with respect to their gold nanorod supercrystal counterparts. COMMUNICATIONSPlanar chiral structures may provide asymmetric transmission for circularly polarized optical waves at normal incidence if the structures are anisotropic and lossy, but the role of loss has not yet been clarifi ed. Here, a typical planar chiral structure is studied, and the mechanism of asymmetric transmission is analyzed. It is demonstrated for the fi rst time that asymmetric transmission can be manipulated by changing the anisotropy of loss.

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Section: Average Widths (±2 μM) Of the Supercrystal Intermediate Layementioning

confidence: 99%

Self‐Assembly of Au@Ag Nanorods Mediated by Gemini Surfactants for Highly Efficient SERS‐Active Supercrystals

Gómez‐Graña

Pérez‐Juste

Alvarez-Puebla³

et al. 2013

Advanced Optical Materials

102

101

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“…[1][2][3] The results obtained for dimeric surfactants stimulated interest in exploring the properties of higher oligomeric analogues, such has tri-and tetrameric surfactants. When compared with conventional single-chain surfactants, these amphiphiles tend to present unusual properties and improved performance.…”

Section: Introductionmentioning

confidence: 99%

“…For instance, gemini surfactants have higher surface activity, a lower critical micelle concentration (cmc), and, in some cases, pronounced viscosifying effects. [1][2][3] The results obtained for dimeric surfactants stimulated interest in exploring the properties of higher oligomeric analogues, such has tri-and tetrameric surfactants. [4][5][6][7][8][9][10][11] Generally, the tendency for this type of surfactant to self-aggregate increases as the number of amphiphilic moieties increases and can display special aggregation behavior to form diverse aggregate geometry, depending on the structure of the amphiphiles.…”

Section: Introductionmentioning

confidence: 99%

Calixarene‐Based Surfactants: Conformational‐Dependent Solvation Shells for the Alkyl Chains

Basílio¹,

García‐Río²

2012

ChemPhysChem

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Thermodynamic parameters obtained from studying the micellization of amphiphilic p-sulfonatocalix[n]arenes were correlated with the alkyl chain length and with the number of monomeric units (n) in the calix[n]arene structure. The micellization Gibbs free energy (ΔG(M)(o)) becomes more negative upon increasing the alkyl chain length of the p-sulfonatocalix[4]arene. This is in agreement with the trend generally observed for other surfactants. However, the ΔG(M)(o) value for transferring one CH(2) group from the bulk aqueous medium to the micelle [ΔG(M)(o)(CH(2))] is lower than the value generally observed for single-chain surfactants, suggesting the existence of intramolecular interactions between the alkyl chains of the free unimers. On the other hand, the critical micelle concentration (cmc; per alkyl chain unit) increased with the increasing number of monomeric units. These results are explained on the basis of the conformation adopted by the calixarene in the bulk solution. The calix[4]arene derivatives are preorganized into the cone conformation, which is favorable for the formation of globular aggregates. The calix[6]arene and calix[8]arene derivatives do not adopt cone conformations. Changing these conformations to the more favorable cone conformer in the aggregates implies an energetic cost that contributes to making ΔG(M)(o) less efficient. In the case of the calix[6]arene derivative this energetic cost is enthalpic, whereas in the case of the octamer it is both enthalpic and entropic. Both the ΔG(M)(o)(CH(2)) value and the change in heat capacity (ΔCp(M)(o)) seem to indicate that for the cone calix[4]arene derivatives all alkyl chains are solvated by the same hydration shell, whereas in the case of the highly flexible calix[8]arene derivative each alkyl chain is individually hydrated.

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“…[2][3][4] In more recent years, particularly after the term "gemini surfactant" had been christened as such, [5] investigation of the compounds has flourished. [2][3][4] In more recent years, particularly after the term "gemini surfactant" had been christened as such, [5] investigation of the compounds has flourished.…”

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confidence: 99%

[12]Annulene Gemini Surfactants: Structure and Self‐Assembly

et al. 2007

Self Cite

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The authors of this Communication wish to alter the proposed structure of annulene 1, a system that had previously been reported by Yamaguchi et al. [1] After one of the authors (F.M.M.) had originally inspected the then available analytical data (1 H and 13 C NMR spectra, elemental analysis, and ESI-MS data), he affirmed that they were (and still are) consistent with the annulene system. In particular, parent mass spectral signals at m/z 531.44353, 587.50648, and 643.56867 for the R = C 12 H 25 , C 14 H 29 , and C 16 H 33 derivatives, respectively, all correspond to the mass of [1ÀCl À ] +. Recently, however, Prof. M. Cristl suggested [2] that the pyridinium salt 2 would be an alternative and more likely possibility. There exists an intriguing ambiguity in this case because 1 and 2 have indistinguishable NMR spectra and elemental analyses and because our [1À2 Cl À ] 2+ base peak and the [2ÀCl À ] + parent peak happen to have identical masses. We are now able to differentiate the two structures through weak 13 C-containing MS signals. These signals have a shift one mass unit higher than the all-12 C signal (consistent with [2ÀCl À ] +) as opposed to 0.5 units higher (consistent with [1À2 Cl À ] 2+). In view of these new data, our peaks at m/z > 500 must, we surmise, arise from dimers of 2 in the gas phase. Fortunately, the altered identity of the compound in no way affects our high-level calculations on the annulene structure. Moreover, our conclusion based on the NMR data, namely, that the terminal methyl groups of the chains loop within a micelle so as to contact the micelle surface, remains valid, although the micelles are now more classical in nature than we had previously envisioned. [1] I. Yamaguchi, Y. Gobara, M. Sato, Org. Lett. 2006, 8, 4279. [2] M. Christl, private communication.

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Gemini-Tenside

Cited by 62 publications

References 73 publications

Self‐Assembly of Au@Ag Nanorods Mediated by Gemini Surfactants for Highly Efficient SERS‐Active Supercrystals

Self‐Assembly of Au@Ag Nanorods Mediated by Gemini Surfactants for Highly Efficient SERS‐Active Supercrystals

Calixarene‐Based Surfactants: Conformational‐Dependent Solvation Shells for the Alkyl Chains

[12]Annulene Gemini Surfactants: Structure and Self‐Assembly

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