Linker Length-Dependent Control of Gemini Surfactant Aqueous Lyotropic Gyroid Phase Stability

Abstract

Network-phase lyotropic liquid crystals (LLCs) derived from the water-directed self-assembly of small molecule amphiphiles comprise a useful class of soft nanomaterials, with wide-ranging applications in structural biology and membrane science. However, few known surfactants enable access to these mesophases over wide temperature and amphiphile concentration phase windows. Recent studies have demonstrated that gemini ("twin tail") dicarboxylate surfactants, in which alkyl carboxylates are covalently linked near the headgroups by a hydrophobic bridge, exhibit increased propensities to form double gyroid network phase LLCs. We demonstrate herein that the lyotropic self-assembly behaviors of gemini dicarboxylates sensitively depend on the linker length, whereby odd-carbon linkers stabilize the double gyroid network LLC over unprecedented amphiphile concentration windows up to ∼45 wt % wide between T ≈ 22-80 °C. These self-assembly phenomena, which arise from the linker length-dependent preferred molecular conformations of these amphiphiles, will broaden the technological applications of these nanostructured LLCs.

Micellar Mimicry of Intermetallic C14 and C15 Laves Phases by Aqueous Lyotropic Self-Assembly

“…This scattering signature remains welldefined and sharp up to T = 80 °C, above which the sharp peaks for this new phase are superposed on a broad scattering peak corresponding to disordered micelles; this two-phase coexistence is precedented and expected in ternary LLCs on the basis of Gibbs phase rule. 46,47 The striking resemblance of this diffraction pattern with those simulated and experimentally observed for the hexagonal C14 Laves phases reported by Hajiw et al in Au nanoparticle superlattices 48 and by Bates and co-workers in diblock polymers 40,41 strongly suggests that this sample comprises an aqueous lyotropic C14 mesophase.…”

Controlled self-assembly of stomatosomes by use of single-component fluorinated dendritic amphiphiles

“…9 and 10 show the best correlation with a bicontinuous cubic phase of double diamond symmetry. This behavior is related to reports on the aggregation behavior of Gemini amphiphiles, 45,69 which also tend to form bicontinuous cubic phases at moderate concentration (however, in this case a double gyroid phase). Such a network formation is obviously favored by double chain compounds.…”

“…The present tetrapod organization is rare and has so far only been identified for lipid-water systems, 43 surfactants 44 and quite recently for a thermotropic liquid crystalline bolaamphiphile. 45 In the case of diblock copolymers the double gyroid structure is energetically favored in general, but for certain stereoregular and graft block copolymers a thermodynamically stable double diamond has also been detected recently. 46,47 One has to emphasize that the three-dimensional organization of the reconstructed bicontinuous structure shows frequent defects.…”

Rapid Stabilization of Immiscible Fluids using Nanostructured Interfaces via Surfactant Association

“…Beyond emulsion stability and colloidal morphology control, mixtures containing immiscible fluids and surfactantlike molecules exhibit intricate phase diagrams containing various morphologies and phase behavior of different universality classes [7][8][9][10]. Furthermore, nontraditional amphiphiles can be used to impart responsive behavior in colloidal systems [11] and contribute to innovations in biomedical, energy, and separation technologies [12][13][14][15][16][17][18][19][20][21]. Since the pioneering work on surfactant association structures by Friberg and co-workers, extensive work has been conducted over the past 50 years in the area of nanostructured phases that form between two interfaces (fluid-fluid and fluid-gas) [22][23][24][25][26][27].…”