Structural studies of poly-γ-benzyl-l-glutamate monolayers by infrared ATR and transmission spectra

Takenaka, Tohru; Harada, Kaoru; Matsumoto, Mutsuo

doi:10.1016/0021-9797(80)90103-4

Cited by 69 publications

(51 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This transition was originally inferred from the presence of a plateau region of constant ⌸ in the surface pressure ͑⌸͒ vs area/monomer ͑A͒ isotherms of the PBLG LM. 11,12,18 Further indirect evidence was provided by Takenaka et al, 18 who LB-deposited the same number of PBLG layers onto solid substrates from both the ''bilayer'' and ''monolayer'' regions in the isotherm and found the ratio of their measured total thicknesses to be ϳ1. 7.…”

Section: Introductionmentioning

confidence: 93%

“…The shown isotherms are very similar to those obtained previously by others for polydisperse samples. 12,13,18,25,46 As indicated in Fig. 2, the ⌸-A phase diagram can be divided into four main regions, each exhibiting a different surface pressure variation with compression.…”

Section: A ⌸-A Isotherms and Surface Imaging By Bammentioning

confidence: 99%

“…Since the ratio of the area/monomer values at the two ends of this coexistence region is close to two, the second phase coexisting with the monolayer phase has been assumed to be a bilayer. 11,12,18,25 Further compression into Region IV (A Ͻϳ11.5 Å 2 /monomer͒ results in a surface pressure increase in the continuous isotherms. However, the relaxation effect is now more significant.…”

Section: Fig 2 ⌸-A Isotherms Atmentioning

confidence: 99%

“…We report here the results of Brewster angle microscopy ͑BAM͒ and extensive x-ray scattering studies conducted in situ on LMs formed by both monodisperse and polydisperse poly͑␥-benzyl L-glutamate͒ ͑PBLG͒, 12,13,18,25 emphasizing the changes in their microscopic structures with lateral compression. The principal results are as follows: ͑i͒ Direct microscopic characterization of the first-order monolayerbilayer transition.…”

Section: Introductionmentioning

confidence: 98%

“…[10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] These rigid rodlike molecules lie down flat on the water surface with 2D nematiclike structures. As such they differ from the aforementioned more conventional amphiphilic LMs and liquid crystal films in that the director n, or principal axis of the molecules, lies within the monolayer plane rather than pointing away from it.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

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

View full text Add to dashboard Cite

. 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.

show abstract

Section: Introductionmentioning

confidence: 93%

Section: A ⌸-A Isotherms and Surface Imaging By Bammentioning

confidence: 99%

Section: Fig 2 ⌸-A Isotherms Atmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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

View full text Add to dashboard Cite

show abstract

Interpretation of IR Spectra of Ultrathin Films

2003

Handbook of Infrared Spectroscopy of Ultrathin Films

View full text Add to dashboard Cite

Generally speaking, IR spectral measurements of ultrathin films are undertaken to determine (i) the chemical identity of adsorbed species (including dissociation fragments); (ii) the geometric or structural arrangement (orientation) of these species and their positions with respect to the surface atoms of the substrate; (iii) their vibrational, rotational, and translational motion on the surface; (iv) the charge distribution and energy level structure of the valence electrons in both adsorbate and substrate; and (v) the effects of external perturbations, such as the electric and magnetic fields, photons, electrons, heating, and surface pressure on factors (i)-(iv) [1]. However, such information cannot be extracted directly from the IR spectra of ultrathin films due to the strong dependence of the shape and relative intensity of the bands on the geometry of the experiment, the optical properties of the substrate, the surroundings, the gradient of the optical properties at the film-substrate interface and in the film itself, as well as on the film thickness, and the particle size in the case of powder or islandlike supports. These effects and their physical background are discussed in Sections 3.1-3.5 and 3.9. In addition, there can be an intensity transfer between modes of coadsorbed species and a change in the band position with surface coverage. This effect is used for determining the mode of the surface filling and the degree of intermixing of different species at the surface (Section 3.6). If the film under study is located at the electrode-solution interface, the resulting spectrum is made up of contributions of all species in the path of radiation that are affected by the electrode potential, which further complicates the interpretation. Apart from technical means (Chapter 4), there exist analytical and mathematical approaches to resolve contributions of different species in such a complex spectrum (Sections 3.7 and 3.8). Another feature of the IR spectra of ultrathin films that is perhaps surprising and unexpected is their sensitivity to the volume fraction, shape, and orientation of inhomogeneities (e.g., pores or inclusions) in the film. Moreover, if the characteristic size of the 140

show abstract

Chiral Monolayers at the Air‐Water Interface

Stewart

Arnett

1982

Topics in Stereochemistry

View full text Add to dashboard Cite

Structural studies of poly-γ-benzyl-l-glutamate monolayers by infrared ATR and transmission spectra

Cited by 69 publications

References 12 publications

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

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

Interpretation of IR Spectra of Ultrathin Films

Chiral Monolayers at the Air‐Water Interface

Contact Info

Product

Resources

About