Preparation and waveguide properties of polyglutamate Langmuir-Blodgett films

Mathy, A.; Mathauer, K.; Wegner, Gerhard; Bubeck, Christoph

doi:10.1016/0040-6090(92)90708-j

Cited by 37 publications

(25 citation statements)

References 23 publications

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“…Copolymers in which short and long side chains, for example, methyl and octadecyl residues are randomly mixed proved to be excellent for LB assembly. [11,[24][25][26][27][28][29][30][31][32][33][34][35][36] The helical conformation of these macromolecules provides the rodlike character as it is schematically indicated in Figure 2. Such copoly(glutamate)s are readily obtained by anionic copolymerization of the corresponding monomer N-carboxyanhydrides (NCA).…”

Section: Basic Concepts and Synthesismentioning

confidence: 99%

“…In the case of PG thick constructs consisting of as many as 1 000 individual layers have been achieved which exhibited optical properties suitable for wave guide type experiments. [25,26,29] Among others Brillouin spectroscopy revealed an elastic modulus, which, in good approximation, is the Young's modulus along the helical axis of the backbones of 12.2 GPa; this value clearly indicates the rigidity of the material. of PcPS are stable and do not undergo structural or chemical changes if annealed for several minutes at temperatures up to 270 8C and may be exposed to ambient conditions over several hours at temperatures up to 150 8C.…”

Section: Constructs Of Internal Nanoscale Architecturementioning

confidence: 99%

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Nanocomposites of Hairy‐Rod Macromolecules: Concepts, Constructs, and Materials

Wegner

2003

Macro Chemistry & Physics

101

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The rational construction of nanocomposites based on so‐called hairy‐rod macromolecules (HRM) is the objective of this review covering 15 years of extensive research at the Max Planck Institute for Polymer Research. HRM are described as shape‐persistent objects, which are processed into ultrathin films by the Langmuir–Blodgett protocol. Transfer of monolayers initially formed on the water surface to solid substrates is understood as a two‐dimensional analogue of an extrusion process giving rise to molecular orientation phenomena. The scope of HRM concerning chemical composition and molecular architecture is reviewed, and examples of how to obtain complex constructs having device functions are given. Recent work on hairy‐rod polyelectrolytes based on poly(p‐phenylene sulfonates)s is summarized as well, and their ability to form hierarchical superstructures in aqueous solution is presented.

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Section: Basic Concepts and Synthesismentioning

confidence: 99%

Section: Constructs Of Internal Nanoscale Architecturementioning

confidence: 99%

Nanocomposites of Hairy‐Rod Macromolecules: Concepts, Constructs, and Materials

Wegner

2003

Macro Chemistry & Physics

101

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“…In recent years, various ␣-helical poly͑L-glutamates͒ have been studied both as LMs on water 23,25,26,[34][35][36][37] and as LB films on solid substrates. 26,34,[37][38][39][40][41][42][43][44][45][46][47][48][49] In most of these studies the primary objective has been to achieve good-quality LB films that possess technologically important properties, 50 such as lateral homogeneity, 23,45 thermal 37,44,47,49 and mechanical 45,48 stability, low defect density, 38,45 and optical anisotropy; 38,39,42 in addition, potential applications, 50,51 for example, as optical wave guides, 38,41,42 optical data storage media, 43,44 and photoresists, 37 have also been suggested. However, despite the high activity in this research area, direct structural characterizations at the intermolecular level have been limited mostly to transferred LB films, as opposed to their LM counterparts, partly due to experimental difficulties invol...…”

Section: Introductionmentioning

confidence: 99%

Structure of poly(γ-benzyl-L-glutamate) monolayers at the gas–water interface: A Brewster angle microscopy and x-ray scattering study

Fukuto

Heilmann

Pershan

et al. 1999

The Journal of Chemical Physics

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. 1999. Structure of poly(\(\gamma\)-benzyl-L-glutamate) monolayers at the gas-water interface: A Brewster angle microscopy and x-ray scattering study. Journal of Chemical Physics 111 (21) This paper reports Brewster angle microscopy ͑BAM͒, x-ray specular reflectivity ͑XR͒, grazing incidence diffraction ͑GID͒ and off-specular diffuse scattering ͑XOSDS͒ measurements of Langmuir monolayers formed on water by both mono-and polydisperse samples of ␣-helical poly͑␥-benzyl L-glutamate͒ ͑PBLG͒ as a function of area/monomer A. The microscopic behavior does not exhibit any discernible effects due to differing dispersity. At low surface densities ͑A Ͼϳ21 Å 2 /monomer, surface pressure ⌸ϭ0͒, BAM images reveal partial surface coverage by solidlike monolayer islands. GID measurements show an interhelix peak corresponding to a local parallel alignment of rodlike PBLG molecules, indicating their tendency to aggregate laterally without external pressure. Compression to AϽ21 Å 2 /monomer first leads to full and uniform surface coverage by the monolayer, followed by a steep rise in ⌸ that is accompanied by a decrease in the interhelix distance. Further compression results in a plateau of constant ⌸ in the ⌸-A isotherm ͑ϳ11.5ϽAϽϳ18.5 Å 2 /monomer, ⌸ϳ9 dyn/cm͒, which has previously been attributed to a first-order monolayer-bilayer transition. The interfacial electron density profiles determined by the XR measurements on both sides of the coexistence plateau provide direct evidence for this transition. On the basis of x-ray scattering results, the film on the high-density side of the plateau is shown to consist of a newly formed incomplete and incommensurate second layer that sits on top of and has lower average density than a homogeneous first layer. GID measurements indicate that the second layer can be characterized by larger interhelix d-spacing than the first layer, while XOSDS measurements on the bilayer suggest that the second layer is microscopically inhomogeneous. For both mono-and bilayers, the analysis of observed GID peak widths indicates that the extent of lateral positional correlations between parallel PBLG rods ranges from a few to no more than ϳ15 interhelix distances, implying short-range order.

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“…Over the last decade, Langmuir-Blodgett ͑LB͒ films of hairy-rod poly͑glutamate͒s have attracted considerable interest because of their potential 1,2,10 for use in optical, [11][12][13] optoelectronic, 14 -16 and sensor device applications. 17,18 LB multilayer films are most often formed through sequential deposition of a LM on a solid substrate.…”

mentioning

confidence: 99%

Internal segregation and side chain ordering in hairy-rod polypeptide monolayers at the gas/water interface: An x-ray scattering study

Fukuto

Heilmann

Pershan

et al. 2003

The Journal of Chemical Physics

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We report studies of the structure and packing of Langmuir monolayers ͑LMs͒ of polypeptide poly͑␥-4-͑n-hexadecyloxy͒benzyl ␣,L-glutamate͒ ͑C16 -O-PBLG͒ on the surface of water. The molecule is a ''hairy rod'' and consists of side attachments of hexadecyloxy chains ͑-O-C16͒ to the rigid rod-like core made up of ␣-helical poly͑␥-benzyl L-glutamate͒ ͑PBLG͒. Measurements include surface pressure ͑⌸͒ versus area/monomer ͑A͒ isotherms, x-ray specular reflectivity ͑XR͒, and grazing incidence diffraction ͑GID͒. In contrast to the LM of bare PBLG on water, which undergoes a monolayer/bilayer transition with increasing ⌸, monolayers of C16 -O-PBLG remain stable up to the highest densities. On the basis of XR and GID results, the structure of the C16 -O-PBLG monolayer is characterized by the following main features. First, hydrophobicity causes the -O-C16 chains to segregate towards the film/gas interface and away from water and the PBLG cores, which sit parallel to and near the water/film interface. Since the attachment position of some of the side chains is at the core/water interface, the segregation forces these chains into the space between neighboring core rods. Compression associated with increasing ⌸ thickens the film but the internally segregated structure is maintained for all ⌸ ͑i.e., Ͼϳ30 dyne/cm͒. Second, the C16 -O-PBLG rods form domains in which the rods are aligned parallel to each other and to the interface. The correlation length for the interhelix positional order of the rods is short and typically comparable to or less than the length of the rods. With increasing ⌸ the spacing d between nearest-neighbor rods decreases linearly with A at high ⌸, indicating a direct correspondence between the macroscopic compressibility and the microscopic interhelix compressibility. Third, as ⌸ increases past ϳ5 dyne/cm, the local packing of tethered -O-C16 chains displays the same herringbone ͑HB͒ order that is common for high-density bulk and monolayer phases of alkyl chains. Various features of the observed GID peaks also imply that the HB order of -O-C16 chains is oriented with respect to the helical axes of aligned PBLG cores. We propose that the HB order is established initially by one-dimensionally confined chains between aligned rods at low ⌸ and grows laterally with compression.

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Preparation and waveguide properties of polyglutamate Langmuir-Blodgett films

Cited by 37 publications

References 23 publications

Nanocomposites of Hairy‐Rod Macromolecules: Concepts, Constructs, and Materials

Nanocomposites of Hairy‐Rod Macromolecules: Concepts, Constructs, and Materials

Structure of poly(γ-benzyl-L-glutamate) monolayers at the gas–water interface: A Brewster angle microscopy and x-ray scattering study

Internal segregation and side chain ordering in hairy-rod polypeptide monolayers at the gas/water interface: An x-ray scattering study

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