Lyotropic Liquid Crystalline Behavior Research Articles

Tailoring the self-assembly of lipid-based lyotropic liquid crystalline mesophases with biocompatible ionic liquid aqueous solutions

Interest in lipid-based lyotropic liquid crystalline nanoparticles (LCNPs) as drug delivery vehicles continues to grow, owing to their unique structural features. The structure of these particles can be controlled to suit specific applications, through tailoring the lipid composition and solvent conditions. Ionic liquids (ILs) are liquid salts comprising tailorable cations and anions, of which some are known to support the self-assembly of amphiphiles, and hence can be used as designer solvents for LCNPs. We employed dynamic light scattering, small angle X-ray scattering, and cryogenic transmission electron microscopy to examine the particle size and lyotropic liquid crystalline mesophase behavior of monoolein (MO)-based LCNPs in aqueous solutions containing 13 choline ILs with a selection of amino acid and carboxylate anions at 6 concentrations 20, 10, 5, 1, 0.33, and 0.16 wt%. Our results show the formation of LCNPs with various liquid crystalline nanostructures, including the inverse bicontinuous primitive cubic (Q2) phase with the Im3m crystallographic space group, the inverse hexagonal (H2), and the inverse discontinuous micellar cubic (I2) phases. The internal nanostructures of the MO nanoparticles depended on three main factors, the anion of the ILs, the IL concentration, and the pH of the solution. This study elucidates the potential application of IL solvents as a powerful tool to tailor the internal nanostructure of MO-based LCNPs, and advances the exploration of IL-enabled responsive LCNPs systems as prospective nanocarriers.

Zwitterionic Polymers toward the Development of Orientation-Sensitive Bioprobes

Dynamics with an orientational degree of freedom are fundamental in biological events. Probes with polarized luminescence enable a determination of the orientation. Lanthanide-doped nanocrystals can provide more precise analysis than quantum dots due to the nonphotoblinking/bleaching nature and the multiple line-shaped emission. However, the intrinsic polarization property of the original nanocrystals often deteriorates in complex physiological environments because the colloidal stability easily breaks and the probes aggregate in the media with abundant salts and macromolecules. Engineering the surface chemistry of the probes is thus essential to be compatible with biosystems, which has remained a challenging task that should be exclusively addressed for each specific probe. Here, we demonstrate a facile and efficient surface functionalization of lanthanide-doped nanorods by zwitterionic block copolymers. Due to the steric interaction and the intrinsic zwitterionic nature of the polymers, high colloidal stability of the zwitterionic nanorod suspension is achieved over wide ranges of pH and concentration of salts, even giving rise to the lyotropic liquid crystalline behavior of the nanorods in physiological media. The shear-aligned ability is shown to be unaltered by the coated polymers, and thus, the strongly polarized emission of Eu3+ is preserved. Besides, biological experiments reveal good biocompatibility of the zwitterionic nanorods with negligible nonspecific binding. This study is a stepping stone for the use of the nanorods as orientation probes in biofluids and validates the strategy of coupling zwitterions to lanthanide-doped nanocrystals for various bioapplications.

Lyotropic Liquid-Crystalline Phases of Sophorolipid Biosurfactants.

Biological amphiphiles derived from natural resources are presently being investigated in the hope that they will someday replace current synthetic surfactants, which are known pollutants of soils and water resources. Sophorolipids constitute one of the main classes of glycosylated biosurfactants that have attracted interest because they are synthesized by non-pathogenic yeasts from glucose and vegetable oils at high titers. In this work, the self-assembly properties of several sophorolipids in water at high concentrations (20-80 wt %), a range so far mostly uncharted, have been investigated by polarized-light microscopy and X-ray scattering. Some of these compounds were found to show lyotropic liquid-crystalline behavior as they display lamellar or hexagonal columnar mesophases. X-ray scattering data shows that the structure of the lamellar phase is almost fully interdigitated, which is likely due to the packing difference between the bulky hydrophilic tails and the more compact aliphatic chains. A tentative representation of the molecular organization of the columnar phase is also given. Moreover, some of these compounds display thermotropic liquid-crystalline behavior, either pure or in aqueous mixtures. In addition, small domains of the lamellar phase can easily be aligned by applying onto them a moderate a.c. electric field, which is a rather unusual feature for lyotropic liquid crystals. Altogether, our work explored the self-assembly liquid-crystalline behavior of sophorolipids at high concentration, which could shed light on the conditions of their potential industrial applications as well as on their biological function.

Nanocomposites of Rigid Polyurethane Foam and Graphene Nanoplates Obtained by Exfoliation of Natural Graphite in Polymeric 4,4'-Diphenylmethane Diisocyanate.

The influence of graphene nanoplates (GNPs) obtained by the ecofriendly exfoliation of natural graphite has been addressed on the mechanical and thermal insulating properties of rigid polyurethane foams (RPUFs). Few-layer GNPs with few defects were prepared in polymeric 4,4′-diphenylmethane diisocyanate (pMDI) under ultrasonication to obtain a GNP/pMDI dispersion. GNP/pMDI dispersions with different GNP concentrations were used to prepare RPUF nanocomposites via in situ polymerization. An important finding is that the GNP/pMDI dispersion exhibits lyotropic liquid crystalline behavior. It was found that the unique orientation of GNPs above the concentration of 0.1 wt% in the dispersion affected the mechanical and thermal insulation properties of the RPUF nanocomposites. GNP/RPUF nanocomposites with GNP concentrations at 0.2 wt% or more showed better thermal insulating properties than neat RPUF. The lyotropic liquid crystalline ordering of GNPs provides stable nucleation for bubble formation during foaming and prevents bubble coalescence. This decreases the average cell size and increases the closed cell content, producing GNP/RPUF nanocomposites with low thermal conductivity. Furthermore, GNPs incorporated into RPUF act as a barrier to radiant heat transfer through the cells, which effectively reduces the thermal conductivity of the resulting nanocomposites. It is expected that the nanocomposite of RPUF investigated in this study can be applied practically to improve the performance of thermal insulation foams.

Magnetic field induced uniaxial alignment of the lyotropic liquid-crystalline PMMA-grafted Fe3O4 nanoplates with controllable interparticle interaction.

Magnetite (Fe3O4) nanoplates with a hexagonal platelet shape were synthesized by two steps: hydrothermal synthesis of iron(iii) oxide (α-Fe2O3) nanoplates followed by wet chemical reduction of the α-Fe2O3 nanoplates. Then, poly(methyl methacrylate) (PMMA) chains were grafted onto the surface of the hexagonal Fe3O4 nanoplates (F) via surface-initiated atom transfer radical polymerization (SI-ATRP), which ensures dispersion stability in organic solvents and ionic liquids. After mixing with 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([Emim+][NTf2−]), a representative ionic liquid, the resulting PMMA-modified F were found to show good lyotropic liquid-crystalline (LC) behaviour in [Emim+][NTf2−] and to exhibit a fast response to the application of an external magnetic field. Ultrasmall-angle synchrotron X-ray scattering (USAXS) measurements verified that the PMMA chain length, the weight ratio of the ionic liquid and the external magnetic field could significantly influence the interparticle distance (ID) of the PMMA-modified F in [Emim+][NTf2−]. In particular, the lyotropic LC phase could be assigned as a nematic phase with a columnar alignment. In addition, the PMMA-modified F maintained a uniaxially aligned nematic columnar structure along the magnetic field direction. Our study also determined the mechanism for the special alignment of the PMMA-modified F under an external magnetic field by analysing the growth axis, the easy magnetic axes, and the interparticle distance of F. The results suggested that the special alignment of the PMMA-modified F was affected by the interparticle interaction caused by the PMMA long chains on F under the magnetic field. Furthermore, the present study revealed that PMMA-modified F exhibited a new magnetic field responsive behaviour that led not only to the formation of a uniaxial alignment structure but also to control of ID with the help of the PMMA soft corona under the application of a magnetic field. These features could prove to be a promising advance towards novel applications of magnetic nanoparticles (NPs), such as functional magnetic fluids, rewritable magnetic switching devices, and smart magneto-electrochemical nanosensors.

Amphotropic liquid-crystalline behaviour of glycolipids in amino acid ionic liquids

ABSTRACTWe examined lyotropic liquid-crystalline behaviour of glycolipids (GLs) with a normal alkyl chain or a diacetylene-functionalised alkyl chain in several amino acid ionic liquids (AAILs). It was found that the mixtures of GL and AAIL form various nanosegregated liquid-crystalline phases, such as smectic, bicontinuous cubic and hexagonal columnar phases, depending on the two-component ratio and AAIL species. The observed liquid-crystalline behaviours were summarised as phase diagrams. It is noteworthy that the employment of amino acid anions with superior hydrogen-bonding ability, such as aspartic and glutamic acid anions, gives a phase diagram with a wide liquid-crystalline region. Comparing with a phase diagram obtained for the GL/water mixtures, we gained insights on the similarity/dissimilarity between water and AAILs as self-organisation media of amphiphiles. For the diacetylene-functionalised molecule, UV irradiation was carried out to progress polymerisation. It is of interest that the polymerisation reaction progressed when the glycolipid formed a smectic phase in an AAIL while a reaction progress was not found when it formed a bicontinuous cubic phase in another AAIL. We believe that AAILs have a great potential to be a liquid media not only for amphiphiles but for various functional materials, such as polymers and colloids, to form novel assemblies.

Design of Dication-Type Amino Acid Ionic Liquids and Their Application to Self-Assembly Media of Amphiphiles

Abstract Dication-type amino acid ionic liquids have been prepared and their physicochemical properties, such as viscosity, glass transition temperature, Kamlet-Taft parameter, ionic conductivity, and refractive index, have been examined. Comparing these properties of the dication-type amino acid ionic liquids with those of corresponding monocation-type ones, we have investigated the effects of the cation-bridging. In addition, the comparison of aliphatic amino acid ionic liquids and aromatic ones has been also examined. By examining lyotropic liquid-crystalline behavior of an amphiphile in these ionic liquids, we have examined how these modifications of ionic liquids make changes in the potential utility of ionic liquids as self-organization media of amphiphiles. It has been found that critical concentrations of lyotropic liquid-crystalline amphiphiles in ionic liquids are successfully reduced by bridging their cations with covalent bonding and/or introducing aromatic-structures into their anions.

Lyotropic Liquid-crystalline Pseudo-polymer Particles with an Iron Oxide Monodispersed Core Controlled in Size and Shapes in Ionic Liquids

Spindle- and disk-shaped pseudo-poly(methyl methacrylate) particles obtained by the surface-initiated atom transfer radical polymerization on α-Fe2O3 or Fe3O4 monodispersed fine particles exhibited lyotropic liquid-crystalline behavior in ionic liquids for a wide range of the mixing ratio. Effects of the size and shape of the particles on the lyotropic liquid-crystalline properties and the nanolevel self-organized structures have also been investigated.

Molecular consideration on the lyotropic liquid crystalline behavior of poly(2-cyano-p-phenylene terephthalamide) solutions in N-methyl-2-pyrrolidone/calcium chloride

The lyotropic liquid crystalline behavior of poly(2-cyano-p-phenylene terephthalamide) (CY-PPTA) solution in the mixture of N-methyl-2-pyrrolidone and calcium chloride was investigated in terms of concentration and temperature. The intrinsic viscosity was decreased with increasing temperature, indicating the contraction of CY-PPTA chain at higher temperature. In dynamic viscosity measurement, the critical concentration (C*) where phase transition to the liquid crystalline phase takes place was decreased with increasing temperature. Above the C*, the dynamic viscosity was decreased and Bingham behavior got more noticeable with increasing concentration due to the development of the liquid crystalline structures. However, Bingham behavior was more notable at higher temperature at a given concentration. The viscosity curves showed the three distinct flow regions suggested by Asada and Onogi and negative first normal stress difference was observed in the range of intermediate shear rates. Open image in new window

A Comprehensive Study on Lyotropic Liquid-Crystalline Behavior of an Amphiphile in 20 Kinds of Amino Acid Ionic Liquids.

We examined the self-organization behavior of a designed amphiphilic molecule in 20 kinds of amino acid ionic liquids composed of 1-butyl-3-methylimidazolium cation and natural amino acid anion ([C4mim][AA]). Addition of [C4mim][AA], regardless of their anion species, to the amphiphile provided homogeneous mixtures showing lyotropic liquid-crystalline (LC) behavior. Upon increasing the component ratio of [C4mim][AA] in the mixtures, a successive change of the mesophase patterns from inverted hexagonal columnar, in some case via bicontinuous cubic, to layered phases was observed. By examining the LC properties at various temperatures and component ratios, we constructed lyotropic LC phase diagrams. Interestingly, the appearance of these phase diagrams is greatly different according to the selection of [AA]. Through comparison, we found that the self-organization behavior of an amphiphile in ionic liquids can be tuned by controlling their ability to form hydrogen-bond, van der Waals, and π-π interactions.

Synthesis and liquid crystalline behavior of bulky poly(methacrylamide)s

ABSTRACTN‐(Bis(4‐(2‐ethylhexyloxy)phenyl)(phenyl)‐methyl)methacrylamide was synthesized and polymerized via reversible addition‐fragmentation chain‐transfer (RAFT) polymerization. The chain‐transfer agent (4‐cyano‐4‐(phenylcarbonothioylthio) pentanoic acid (CPADB)), combined with a chiral additive, and a radical initiator yielded polymers with dispersities between 1.2 and 1.4. At low concentrations, the polymers are soluble in hexanes and chloroform while at higher concentrations they swell in these solvents. Characterization of the polymers by wide‐angle X‐ray scattering (WAXS) revealed an interplanar distance of 19.0 Å. The WAXS data combined with polarized optical microscopy support a lamellar crystallization and lyotropic liquid crystalline behavior in hexanes and chloroform. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 2563–2568

Liquid crystals of self-assembled DNA bottlebrushes.

Early theories for bottlebrush polymers have suggested that the so-called main-chain stiffening effect caused by the presence of a dense corona of side chains along a central main chain should lead to an increased ratio of effective persistence length (lp,eff) over the effective thickness (Deff) and, hence, ultimately to lyotropic liquid crystalline behavior. More recent theories and simulations suggest that lp,eff ∼ Deff, such that no liquid crystalline behavior is induced by bottlebrushes. In this paper we investigate experimentally how lyotropic liquid crystalline behavior of a semiflexible polymer is affected by a dense coating of side chains. We use semiflexible DNA as the main chain. A genetically engineered diblock protein polymer C4K12 is used to physically adsorb long side chains on the DNA. The C4K12 protein polymer consists of a positively charged binding block (12 lysines, K12) and a hydrophilic random coil block of 400 amino acids (C4). From light scattering we find that, at low ionic strength (10 mM Tris-HCl), the thickness of the self-assembled DNA bottlebrushes is on the order of 30 nm and the effective grafting density is 1 side chain per 2.7 nm of DNA main chain. We find these self-assembled DNA bottlebrushes form birefringent lyotropic liquid crystalline phases at DNA concentrations as low as 8 mg/mL, roughly 1 order of magnitude lower than for bare DNA. Using small-angle X-ray scattering (SAXS) we show that, at DNA concentrations of 12 mg/mL, there is a transition to a hexagonal phase. We also show that, while the effective persistence length increases due to the bottlebrush coating, the effective thickness of the bottlebrush increases even more, such that in our case the bottlebrush coating reduces the effective aspect ratio of the DNA. This is in agreement with theoretical estimates that show that, in most cases of practical interest, a bottlebrush coating will lead to a decrease of the effective aspect ratio, whereas, only for bottlebrushes with extremely long side chains at very high grafting densities, a bottlebrush coating may be expected to lead to an increase of the effective aspect ratio.

Effects of ionic group incorporation into model polypeptide, poly(γ-benzyl-L-glutamate) (PBLG)

Effects of incorporation of ionic groups and ionic interactions to a model polypeptide, poly(γ-benzyl-L-glutamate) (PBLG), are studied. Partial conversion of γ-benzyl-L-glutamate residues to glutamic acid residues does not change molecular conformation (α-helix) and shows little change in properties. By contrast, partial conversion to sodium glutamates (ionic groups) leads to conversion from a rigid rod to a semi-flexible rod at low ion contents and causes significant changes in thermal stability and birefringence. In solution, lyotropic liquid crystalline behavior of PBLG is lost at ion content as low as 3.2 mol %. In solid, birefringence is still observed at this ion content, suggesting thermotropic liquid crystallinity of this ionic PBLG. Molecular composites made of ionic PBLG as a reinforcer and poly(4-vinylpyridine) (PVP) as a matrix polymer show significant enhancement in strength and toughness as a result of ion-dipole interactions between the component polymers.

Design of Amphiphilic Zwitterions Forming Liquid-Crystalline Phases and Effects of Lithium Salt Addition on Their Phase Behavior

Abstract We prepared pyridinium-based amphiphilic zwitterions and examined their liquid-crystalline (LC) phase behavior in the presence and absence of lithium salts. Addition of lithium salts induced nanosegregated LC phases such as bicontinuous cubic phase and smectic phase depending on the anion species of the lithium salts. For example, an equimolar mixture of dodecylcarbamoyl-1-(4-sulfobutyl)pyridinium betaine and lithium bis(trifluoromethanesulfonyl)imide (LiTf2N) exhibited a bicontinuous cubic phase between 40 and 100 °C. The exhibition of these nanosegregated phases was attributed to the formation of an ionic liquid-like ion pair composed of the pyridinium cation and the Tf2N anion. The preferential interaction between the pyridinium cation and the Tf2N anion was confirmed with Raman spectroscopic measurement. Moreover, the amphiphilic zwitterions were found to show not only thermotropic LC behavior but also lyotropic LC behavior in the presence of polar solvents such as protic ionic liquids. The results presented here indicate that the combination of amphiphilic zwitterions and suitable additive ions is a potential method to construct nanostructured LC materials showing tuneable phase behavior.

Liquid Crystalline and Shear-Induced Properties of an Aqueous Solution of Graphene Oxide Sheets

We demonstrated here the lyotropic liquid crystalline behavior of an aqueous solution of graphene oxide (GO) sheets. Scanning electron microscope experiments revealed GO sheets self-assembled into fiber-like or sheet-like structures at different concentrations under flow conditions. As a result, the solution viscosity decreased dramatically with increasing shear stress.

Gelation, Phase Behavior, and Dynamics of β-Lactoglobulin Amyloid Fibrils at Varying Concentrations and Ionic Strengths

We have investigated the thermodynamic and dynamic behavior of multistranded β-lactoglobulin protein fibrils in water, by combining static, dynamic, and depolarized dynamic light scattering (SLS, DLS, DDLS), small angle neutron scattering (SANS), rheology, and cryogenic transmission electron microscopy (cryo-TEM). We focus on the region of the phase diagram at which ionic strength and concentration changes induce transitions in gelation and lyotropic liquid crystalline behavior. An increase in ionic strength, induced by NaCl salt, progressively causes the phase transitions from nematic (N) to gel (G) phases; a further increase causes the transition to a translucent phase and to a macroscopic phase separation, respectively. An increase in fibril concentration induces first a phase transition from an isotropic (I) to a nematic phase (N); a further increase induces the formation of a gel phase. The protein gel strength is investigated by rheology measurements. SANS and osmotic compressibility calculated by SLS measurements clearly capture the main features of the IN transition of β-lactoglobulin protein fibrils. The form and structure factors measured by scattering experiments are analyzed by the polymer reference interaction site model (PRISM). Dynamics of the protein fibrils at different concentrations, measured by polarized and depolarized dynamic light scattering, show both individual and collective diffusion after the isotropic-nematic transition. Above this transition, cryo-TEM images further demonstrate the alignment of the protein fibrils, which is quantified by a 2D order parameter. This work discusses comprehensively, both experimentally and theoretically, the thermodynamics and dynamic features of β-lactoglobulin amyloid fibrils in a vast region of the concentration-ionic strength phase diagram.

A new fluorinated inositol-based surfactant

Carbohydrates are versatile materials of natural origin and thus they are interesting hydrophilic head groups for surfactants. Especially myo-inositol derivatives have advantages over pyranosidic or furanosidic sugar derivatives, namely a higher thermal and chemical stability. The main disadvantage turned out to be the poor water solubility of myo-inositol surfactants, which, however, can be overcome by introducing an oligoethylene oxide group between the inositol head group and the apolar chain. Our goal was to combine the favourable properties of surfactants based on myo-inositol with those of fluorinated surfactants, which are becoming increasingly important as CO2 solvation mediators or stabilizers for reverse water-in-fluorocarbon microemulsions. Thus we synthesized a new surfactant which combines the three units of interest, namely an inositol head group, an oligoethylene oxide linker to provide sufficient solubility and a fluorinated chain. We studied the thermotropic and lyotropic liquid crystalline behaviour as well as the surface tension and compared these results with those of a fully protonated surfactant which has a similar structure.

Comparison of Aggregation Behaviors of a Phytosterol Ethoxylate Surfactant in Protic and Aprotic Ionic Liquids

Two different room-temperature ionic liquids (ILs), the protic ethylammonium nitrate (EAN) and the aprotic 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF(4)), have been employed to investigate the solvent protonation effect on aggregation behaviors of a phytosterol ethoxylate surfactant (BPS-10). The calculated thermodynamic parameters based on surface tension measurements present a stronger solvophobic interaction in EAN than that in [Bmim]BF(4) and disclose different driving forces for micelle formation. In addition, the polarized optical microscopy and small-angle X-ray scattering techniques are used to characterize the phase structures formed in both systems at 25 °C. Due to the H-bonding networks in protic EAN, BPS-10 exhibits a lyotropic liquid-crystalline behavior different from that in [Bmim]BF(4). Results obtained from the rheological measurements reflect a more viscoelastic nature of lyotropic liquid-crystalline phases in EAN. The obtained results indicate that the protic EAN behaves more effective than [Bmim]BF(4) to promote the nonionic BPS-10 aggregation.

Nonionic diethanolamide amphiphiles with saturated hydrocarbon chains: Neat crystalline and lyotropic liquid crystalline phase behavior

The solid state and lyotropic phase behavior of a series of nonionic diethanolamide amphiphiles with increasing saturated hydrocarbon chain length (lauroyl, myristoyl, palmitoyl, and stearoyl) has been examined. All four saturated diethanolamide amphiphiles form a crystalline solid with two or three different polymorphic crystalline forms at room temperature. Melting points and associated enthalpies for these four amphiphiles increased with increasing chain length. Approximate partial binary phase diagrams have been constructed for each amphiphile/water system by combining Cross-Polarized Optical Microscopy (POM) and Small-Angle X-ray Scattering (SAXS) results. In the presence of water, all four diethanolamides form an Lα phase, between 10% and 50% water content, and an L2 phase with decreasing hydration and increasing temperature. In addition to the Lα and L2 phases, the shorter chain diethanolamide amphiphiles (lauroyl and myristoyl) also display a normal micellar phase (L1) at higher water contents, occurring to lower temperatures than the Lα phase. By examining the effect of subtle molecular changes on both neat and lyotropic phase behavior, amphiphiles can be designed with properties tailored to a desired application.

Chelating DTPA amphiphiles: ion-tunable self-assembly structures and gadolinium complexes

A series of chelating amphiphiles and their gadolinium (Gd(III)) metal complexes have been synthesized and studied with respect to their neat and lyotropic liquid crystalline phase behavior. These amphiphiles have the ability to form ion-tunable self-assembly nanostructures and their associated Gd(III) complexes have potential as magnetic resonance imaging (MRI) contrast enhancement agents. The amphiphiles are composed of diethylenetriaminepentaacetic acid (DTPA) chelates conjugated to one or two oleyl chain(s) (DTPA-MO and DTPA-BO), or isoprenoid-type chain(s) of phytanyl (DTPA-MP and DTPA-BP). The thermal phase behavior of the neat amphiphiles was examined by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and cross polarizing optical microscopy (POM). Self-assembly of neat amphiphiles and their associated Gd complexes, as well as their lyotropic phase behavior in water and sodium acetate solutions of different ionic strengths, were examined by POM and small and wide angle X-ray scattering (SWAXS). All neat amphiphiles exhibited lamellar structures. The non-complexed amphiphiles showed a variety of lyotropic phases depending on the number and nature of the hydrophobic chain in addition to the ionic state of the hydration. Upon hydration with increased Na-acetate concentration and the subtle changes in the effective headgroup size, the interfacial curvature of the amphiphile increased, altering the lyotropic liquid crystalline structures towards higher order mesophases such as the gyroid (Ia3d) bicontinuous cubic phase. The chelation of Gd with the DTPA amphiphiles resulted in lamellar crystalline structures for all the neat amphiphiles. Upon hydration with water, the Gd-complexed mono-conjugates formed micellar or vesicular self-assemblies, whilst the bis-conjugates transformed only partially into lyotropic liquid crystalline mesophases.