Swollen liquid-crystalline lamellar phase based on extended solid-like sheets

Gabriel, Jean‐Christophe P.; Camerel, Franck; Lemaire, Bruno J.; Desvaux, Hervé; Davidson, Patrick; Batail, Patrick

doi:10.1038/35097046

Cited by 256 publications

(294 citation statements)

References 26 publications

Supporting

Mentioning

270

Contrasting

Unclassified

Order By: Relevance

“…In all of these systems, covalent cross-linking between chemically heterogeneous parts of the molecules, such as a hydrophobic chain and hydrophilic head, introduce a molecular frustration that acts to suppress macroscopic phase separation and instead drives the formation of microphase separated structures such as membranes. In contrast to the extensive work on amphiphilic self-assembly, the possibility of membrane formation from nonamphiphilic components remains relatively unexplored (29,36,37).…”

Section: Discussionmentioning

confidence: 99%

Entropy driven self-assembly of nonamphiphilic colloidal membranes

Barry

Dogic

2010

Proc. Natl. Acad. Sci. U.S.A.

129

186

View full text Add to dashboard Cite

We demonstrate that homogeneous monodisperse rods in the presence of attractive interactions assemble into equilibrium 2D fluid-like membranes composed of a one-rod length thick monolayer of aligned rods. Unique features of our system allow us to simultaneously investigate properties of these membranes at both continuum and molecular lengthscales. Analysis of thermal fluctuations at continuum lengthscales yields the membranes' lateral compressibility and bending rigidity and demonstrates that the properties of colloidal membranes are comparable to those of traditional lipid bilayers. Fluctuations at molecular lengthscales, in which single rods protrude from the membrane surface, are directly measured by comparing the positions of individual fluorescently labeled rods within a membrane to that of the membrane's continuum conformation. As two membranes approach each other in suspension, protrusion fluctuations are suppressed leading to effective repulsive interactions. Motivated by these observations, we propose an entropic mechanism that explains the stability of colloidal membranes and offers a general design principle for the self-assembly of 2D nanostructured materials from rod-like molecules.colloids | liquid crystals | nanorods | depletion interaction I n hard-body fluids, interactions between individual particles are described by a steep repulsive potential that imposes an infinite energetic penalty for any overlapping particles. It follows that any accessible state of a hard particle fluid has no internal energy and that minimizing the free energy of such a system is equivalent to maximizing its entropy. Hard particles have served as essential model systems for our understanding of the liquid and solid state, demonstrating the existence of nematic and smectic phases in hard rods (1, 2) and a 3D crystalline phase in hard spheres (3). These results exemplify the counterintuitive yet well established notion that entropy alone can drive the self-assembly of ordered structures. In this paper, we extend these ideas of entropic self-assembly to a equilibrium structure, a colloidal membrane. We demonstrate that in the presence of attractive (depletion) interactions mediated by nonadsorbing polymer, monodisperse rod-like colloids (filamentous viruses) spontaneously assemble into 2D membranes. In contrast to the previous examples of entropic self-assembly, in which the constituent molecules assemble into 3D structures, the self-assembly of homogeneous rods into colloidal membranes is self-limited to two dimensions, similar to what is observed for the assembly of amphiphilic lipids into ubiquitous biological membranes (4). However, unlike amphiphilic molecules that have a heterogeneous molecular structure, all the molecules involved in assembly of colloidal membranes are homogeneous, suggesting that geometry as well as chemical heterogeneity can be used to design pathways for self-assembly of various molecular species (5).In what follows, we utilize two unique features of our model experimental virus/polymer system t...

show abstract

Section: Discussionmentioning

confidence: 99%

Entropy driven self-assembly of nonamphiphilic colloidal membranes

Barry

Dogic

2010

Proc. Natl. Acad. Sci. U.S.A.

129

186

View full text Add to dashboard Cite

show abstract

“…Charged platelet suspensions, such as swelling clays [1][2][3][4][5][6][7][8], disk-like mineral crystallites [9][10][11][12][13][14][15][16] or exfoliated nanosheets [17][18][19][20][21][22] abound in natural as well as industrial environments. Such minerals can be found in various particle sizes varying between 10 nm up to a few micrometers and the majority of them have a platelet-like shape with high aspect ratio, typically ranging between 20 and 1000.…”

Section: Introductionmentioning

confidence: 99%

Interplay of anisotropy in shape and interactions in charged platelet suspensions

Jabbari-Farouji

Weis

Levitz

et al. 2014

The Journal of Chemical Physics

Self Cite

View full text Add to dashboard Cite

Motivated by the intriguing phase behavior of charged colloidal platelets, we investigate the structure and dynamics of charged repulsive disks by means of Monte-Carlo simulations. The electrostatic interactions are taken into account through an effective two-body potential, obtained within the nonlinear Poisson-Boltzmann formalism, which has the form of anisotropic screened Coulomb potential. Recently, we showed that the original intrinsic anisotropy of the electrostatic potential in competition with excluded volume effects leads to a rich phase behavior that not only includes various liquid-crsytalline phases but also predicts the existence of novel structures composed of alternating nematic-antinematic sheets. Here, we examine the structural and dynamical signatures of each of the observed structures for both translational and rotational degrees of freedom. Finally, we discuss the influence of effective charge value and our results in relation to experimental findings on charged platelet suspensions.

show abstract

“…[1][2][3][4] The presence of the nanoparticle and the interaction of the polymer with the particle as well as the particle orientation in an aqueous precursor phase may lead to a variety of ordered composite materials in the bulk or film. 2,5 Anisotropic clay particles promote supramolecular organization 2,6 similar to other systems such as liquid crystalline polymers, 7 surfactants, 8 block copolymers [9][10][11] and peptides. 12 Depending on the concentration of polymer and clay, the polymer type and molecular weight, the clay size, shape and surface chemistry, one may generate a variety of dispersions, 13,14 solutions, 15 smart gels, 16,18 shake gels, 19,20 glues [16][17][18] and gum-like gels [16][17][18]21,22 all of which may be excellent precursors for hierarchically structured bulk materials.…”

Section: Introductionmentioning

confidence: 99%

Supramolecular structures in nanocomposite multilayered films

Stefanescu

Dundigalla

Ferreiro

et al. 2006

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

We investigate the multilayered structures of poly(ethylene)oxide/montmorillonite nanocomposite films made from solution. The shear orientation of a polymer-clay network in solution combined with simultaneous solvent evaporation leads to supramolecular multilayer formation in the film. The resulting films have highly ordered structures with sheet-like multilayers on the micrometer length scale. The polymer covered clay platelets were found to orient in interconnected blob-like chains and layers on the nanometer length scale. Inside the blobs, scattering experiments indicate the polymer covered and stacked clay platelets oriented in the plane of the film. The polymer is found to be partially crystalline although this is not visible by optical microscopy. Atomic force microscopy suggests that the excess polymer, which is not directly adsorbed to the clay, is wrapped around the stacked platelets building blobs and the polymer also interconnects the polymer-clay layers. Overall our results suggest the re-intercalation of clay platelets in films made from exfoliated polymer-clay solutions as well as the supramolecular order and hierarchical structuring on the nanometer, via micrometer to the centimeter length scale.

show abstract

Swollen liquid-crystalline lamellar phase based on extended solid-like sheets

Cited by 256 publications

References 26 publications

Entropy driven self-assembly of nonamphiphilic colloidal membranes

Entropy driven self-assembly of nonamphiphilic colloidal membranes

Interplay of anisotropy in shape and interactions in charged platelet suspensions

Supramolecular structures in nanocomposite multilayered films

Contact Info

Product

Resources

About