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Sauthier G, Segura JJ, Fraxedas J, Verdaguer A. Hydrophobic coating of mica by stearic acid vapor deposition. Colloids Surf A Physicochem Eng Asp 2014. [DOI: 10.1016/j.colsurfa.2013.11.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Formation and regulation of supramolecular chirality in organogel via addition of tartaric acid. ACTA ACUST UNITED AC 2012. [DOI: 10.1007/s11434-012-5436-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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3
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Zhang S, Yang S, Lan J, Yang S, You J. Helical nonracemic tubular coordination polymer gelators from simple achiral molecules. Chem Commun (Camb) 2008:6170-2. [DOI: 10.1039/b813375a] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Structure and thermal stability of Langmuir–Blodgett films of barium arachidate. Colloids Surf A Physicochem Eng Asp 2005. [DOI: 10.1016/j.colsurfa.2004.10.103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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5
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Bantchev GB, Schwartz DK. Structure of beta-casein layers at the air/solution interface: atomic force microscopy studies of transferred layers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:11692-11697. [PMID: 15595799 DOI: 10.1021/la048380f] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We report the nanoscale structural changes associated with the interfacial gelation of adsorbed beta-casein layers as a function of aging time. Adsorbed layers were transferred to solid supports and imaged by atomic force microscopy. The aging of the layer was accompanied by the formation of distinct disk-shaped protein nanoparticles ( approximately 20 nm in diameter). Under conditions where a gelled layer was expected (from previous interfacial rheology experiments), we observed ordering of the particles and the formation of elongated aggregates or linear rows. Brewster angle microscopy images were also obtained during the adsorption and gelation processes and during the degradation of the protein layer following addition of the surfactant sodium dodecyl sulfate (SDS). If SDS was added prior to interfacial protein gelation, the layer developed a foamlike morphology consistent with a fluid interfacial protein layer. However, if SDS was added after gelation, the protein layer was observed to fracture, consistent with the behavior of a solid phase.
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Affiliation(s)
- Grigor B Bantchev
- Department of Chemical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309-0424, USA
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Ribó JM, Crusats J, Sagués F, Claret J, Rubires R. Chiral sign induction by vortices during the formation of mesophases in stirred solutions. Science 2001; 292:2063-6. [PMID: 11408653 DOI: 10.1126/science.1060835] [Citation(s) in RCA: 527] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Achiral diprotonated porphyrins, forming homoassociates in aqueous solution, lead to spontaneous chiral symmetry breaking. The unexpected result is that the chirality sign of these homoassociates can be selected by vortex motion during the aggregation process. This result is confirmed by means of circular dichroism spectra. These experimental findings are rationalized in terms of the asymmetric influence of macroscopic forces on bifurcation scenarios and by considering the specific binding characteristics of the porphyrin units to form the homoassociates.
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Affiliation(s)
- J M Ribó
- Department of Organic Chemistry, Department of Physical Chemistry, University of Barcelona, Marti i Franquès 1, 08028-Barcelona, Catalonia, Spain.
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Dynarowicz-Latka P, Dhanabalan A, Oliveira ON. Modern physicochemical research on Langmuir monolayers. Adv Colloid Interface Sci 2001; 91:221-93. [PMID: 11392357 DOI: 10.1016/s0001-8686(99)00034-2] [Citation(s) in RCA: 223] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Recent developments in characterising Langmuir monolayers of a variety of film-forming materials and employing several physicochemical techniques are reviewed. The extension of the LB method to non-amphiphilic substances, especially macromolecular systems, has increased the need of a thorough understanding of Langmuir film properties, which requires characterising techniques that provide complementary information. Since there is vast literature in the subject, only selected examples are given of results that illustrate the potential of the techniques discussed.
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Peng JB, Barnes GT, Gentle IR. The structures of Langmuir-Blodgett films of fatty acids and their salts. Adv Colloid Interface Sci 2001; 91:163-219. [PMID: 11392356 DOI: 10.1016/s0001-8686(99)00031-7] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Recent advances in several experimental techniques have enabled detailed structural information to be obtained for floating (Langmuir) monolayers and Langmuir-Blodgett films. These techniques are described briefly and their application to the study of films of fatty acids and their salts is discussed. Floating monolayers on aqueous subphases have been shown to possess a complex polymorphism with phases whose structures may be compared to those of smectic mesophases. However, only those phases that exist at high surface pressures are normally used in Langmuir-Blodgett (LB) deposition. In single LB monolayers of fatty acids and fatty acid salts the acyl chains are in the all-trans conformation with their long axes normal to the substrate. The in-plane molecular packing is hexagonal with long-range bond orientational order and short-range positional order: known as the hexatic-B structure. This structure is found irrespective of the phase of the parent floating monolayer. The structures of multilayer LB films are similar to the structures of their bulk crystals, consisting of stacked bilayer lamellae. Each lamella is formed from two monolayers of fatty acid molecules or ions arranged head to head and held together by hydrogen bonding between pairs of acids or ionic bonding through the divalent cations. With acids the acyl chains are tilted with respect to the substrate normal and have a monoclinic structure, whereas the salts with divalent cations may have the chains normal to the substrate or tilted. The in-plane structures are usually centred rectangular with the chains in the trans conformation and packed in a herringbone pattern. Multilayer films of the acids show only a single-step order-disorder transition at the melting point. This temperature tends to rise as the number of layers increases. Complex changes occur when multilayer films of the salts are heated. Disorder of the chains begins at low temperatures but the arrangement of the head groups does not alter until the melting temperature is reached. Slow heating to a temperature just below the melting temperature gives, with some salts, a radical change in phase. The lamellar structure disappears and a new phase consisting of cylindrical rods lying parallel to the substrate surface and stacked in a hexagonal pattern is formed. In each rod the cations are aligned along the central axis surrounded by the disordered acyl chains.
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Affiliation(s)
- J B Peng
- Department of Chemistry, The University of Queensland, Brisbane, Australia
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9
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Fenter P, Eberhardt A, Liang KS, Eisenberger P. Epitaxy and chainlength dependent strain in self-assembled monolayers. J Chem Phys 1997. [DOI: 10.1063/1.473281] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Viswanathan R, Madsen LL, Zasadzinski JA, Schwartz DK. Liquid to hexatic to crystalline order in Langmuir-Blodgett films. Science 1995; 269:51-4. [PMID: 7604278 DOI: 10.1126/science.7604278] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Atomic force microscope images of zinc arachidate (ZnA2) Langmuir-Blodgett films show that three- and five-layer films are "hexatic," with long-range bond-orientational order and short-range positional correlations of three to five lattice repeats. The monolayer in contact with the substrate is disordered. Films of seven or more layers of ZnA2 are crystalline. A population of dislocations, most likely originating at the substrate, disrupts the positional but not the orientational order of the lattice, leading to hexatic layers intermediate between crystal and liquid. The influence of the substrate propagates farther into ZnA2 films than into cadmium arachidate films because the molecular cohesion is much weaker in ZnA2 than in cadmium arachidate, as evidenced by a less dense molecular packing.
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Affiliation(s)
- R Viswanathan
- Department of Chemical Engineering, University of California, Santa Barbara 93106, USA
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11
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Stiger R, Virtanen J, Lee S, Virtanen S, Penner R. Scanning tunneling microscopic observations of commensurate crystalline structures for horizontally deposited cadmium stearate bilayers on graphite. Anal Chim Acta 1995. [DOI: 10.1016/0003-2670(94)00525-q] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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12
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Tsukruk VV, Reneker DH. Scanning probe microscopy of organic and polymeric films: from self-assembled monolayers to composite multilayers. POLYMER 1995. [DOI: 10.1016/0032-3861(95)90925-r] [Citation(s) in RCA: 126] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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13
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Applications of atomic force microscopy to structural characterization of organic thin films. Colloids Surf A Physicochem Eng Asp 1994. [DOI: 10.1016/0927-7757(94)80002-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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14
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Maliszewskyj NC, Heiney PA, Josefowicz JY, McCauley JP, Smith AB. Unexpected Square Symmetry Seen by Atomic Force Microscopy in Bilayer Films of Disk-Like Molecules. Science 1994; 264:77-9. [PMID: 17778138 DOI: 10.1126/science.264.5155.77] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Thin films of disk-shaped molecules are expected to display anisotropic optical and transport properties, leading to applications in optical display or sensor technologies. Bilayer Langmuir-Blodgett films of monomeric triphenylene mesogens have been studied by atomic force microscopy. The triphenylene cores of the constituent molecules tend to promote the formation of columnar structures in the plane of the substrate and along the direction of deposition of the film. Atomic force microscopy images of bilayer Langmuir-Blodgett films revealed two types of structure, one corresponding to an aligned columnar structure and the other to an unusual square lattice, which may result from the superposition of columnar structures in adjacent layers that intersect at near right angles. Annealing such bilayers near the melting point of the bulk compound improved the structural ordering by reducing the angular spread of orientations associated with the well-developed columnar structure in some areas and by producing a more distinct square lattice in other areas of the sample.
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Abstract
The controlled transfer of organized monolayers of amphiphilic molecules from the airwater interface to a solid substrate was the first molecular-scale technology for the creation of new materials. However, the potential benefits of the technology envisioned by Langmuir and Blodgett in the 1930s have yet to be fully realized. Problems of reproducibility and defects and the lack of basic understanding of the packing of complex molecules in thin films have continued to thwart practical applications of Langmuir-Blodgett films and devices made from such films. However, modern high-resolution x-ray diffraction and scanning probe microscopy have proven to be ideal tools to resolve many of the basic questions involving thin organic films. Here, studies are presented of molecular order and organization in thin films of fatty acid salts, the prototypical system of Katharine Blodgett. Even these relatively simple systems present liquid, hexatic, and crystalline order; van der Waals and strained layer epitaxy on various substrates; wide variations in crystal symmetry and interfacial area with counterions; modulated superstructures; and coexisting lattice structures. The wide variety of possible structures presents both a challenge and an opportunity for future molecular design of organic thin-film devices.
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Affiliation(s)
- J A Zasadzinski
- Department of Chemical and Nuclear Engineering, University of California, Santa Barbara 93106
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Bourdieu L, Ronsin O, Chatenay D. Response
: Examining Langmuir-Blodgett Films with Atomic Force Microscopy. Science 1994. [DOI: 10.1126/science.263.5150.1158-b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- L. Bourdieu
- Institut Curie, Section de Physique et Chimie, Laboratoire de Physico-Chimie des Surfaces et Interfaces, Unité Associée, CNRS 1379 and Université Paris VI, 11, rue Pierre et Marie Curie, 75005 Paris, France
| | - O. Ronsin
- Institut Curie, Section de Physique et Chimie, Laboratoire de Physico-Chimie des Surfaces et Interfaces, Unité Associée, CNRS 1379 and Université Paris VI, 11, rue Pierre et Marie Curie, 75005 Paris, France
| | - D. Chatenay
- Institut Curie, Section de Physique et Chimie, Laboratoire de Physico-Chimie des Surfaces et Interfaces, Unité Associée, CNRS 1379 and Université Paris VI, 11, rue Pierre et Marie Curie, 75005 Paris, France
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Bourdieu L, Ronsin O, Chatenay D. Response
: Examining Langmuir-Blodgett Films with Atomic Force Microscopy. Science 1994. [DOI: 10.1126/science.263.5150.1158.b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- L. Bourdieu
- Institut Curie, Section de Physique et Chimie, Laboratoire de Physico-Chimie des Surfaces et Interfaces, Unité Associée, CNRS 1379 and Université Paris VI, 11, rue Pierre et Marie Curie, 75005 Paris, France
| | - O. Ronsin
- Institut Curie, Section de Physique et Chimie, Laboratoire de Physico-Chimie des Surfaces et Interfaces, Unité Associée, CNRS 1379 and Université Paris VI, 11, rue Pierre et Marie Curie, 75005 Paris, France
| | - D. Chatenay
- Institut Curie, Section de Physique et Chimie, Laboratoire de Physico-Chimie des Surfaces et Interfaces, Unité Associée, CNRS 1379 and Université Paris VI, 11, rue Pierre et Marie Curie, 75005 Paris, France
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Schwartz DK, Viswanathan R, Zasadzinski JA. Examining Langmuir-Blodgett Films with Atomic Force Microscopy. Science 1994. [DOI: 10.1126/science.263.5150.1158.a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- D. K. Schwartz
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90024, USA
| | - R. Viswanathan
- Department of Chemical and Nuclear Engineering, University of California, Santa Barbara, CA 93106, USA
| | - J. A. Zasadzinski
- Department of Chemical and Nuclear Engineering, University of California, Santa Barbara, CA 93106, USA
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Bourdieu L, Ronsin O, Chatenay D. Examining Langmuir-Blodgett Films with Atomic Force Microscopy. Science 1994; 263:1158-9. [PMID: 17831630 DOI: 10.1126/science.263.5150.1158-a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Viswanathan R, Zasadzinski JA, Schwartz DK. Strained-layer van der Waals epitaxy in a Langmuir-Blodgett film. Science 1993; 261:449-52. [PMID: 8392751 DOI: 10.1126/science.8392751] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Atomic force microscope images of Langmuir-Blodgett films of lead and manganese fatty acid salts show that these monolayers have long-range order and are oriented with respect to the mica substrate, although the lattice symmetries of the monolayers and substrate are dramatically different. The surface lattice of sequentially thicker films evolves toward the bulk structure while retaining the substrate alignment. This behavior is in distinct contrast to films of cadmium fatty acid salts on mica, or all films on amorphous silicon oxide, in which the monolayer structure is disordered and a three-layer-thick film displays the bulk structure.
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Affiliation(s)
- R Viswanathan
- Department of Chemical and Nuclear Engineering, University of California, Santa Barbara 93106
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