Relation between phase diagram, crystallization, and optical properties of cyanine dye/stearic acid mixed monolayers

Journal Article · Thu Jun 01 00:00:00 EDT 1989 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100348a037· OSTI ID:6751608

Duschl, C; Kemper, D; Frey, W; Meller, P; Ringsdorf, H; Knoll, W ^[1]

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1. Max-Planck-Institut fuer Polymerforschung, Mainz (Germany, F.R.) Johannes-Gutenberg-Universitaet, Mainz (Germany, F.R.) Technische Universitaet Muenchen, Garching (Germany, F.R.)

The phase behavior of cyanine dye monolayers mixed with stearic acid as cosurfactant was investigated at various mole fractions, x, by recording pressure-area isotherms at the water-air interface. The resulting pressure-composition phase diagram shows a eutectic behavior with mixed crystal formation. In the miscibility gap ranging from x {approx} 0.3 to x {approx} 0.95 above the eutectic pressure {pi}{sub e} = 40 mN{center dot}m{sup {minus}1} the two coexisting crystal modifications are characterized (among other techniques) by fluorescence microscopy and, after transfer to a suitable substrate, by electron diffraction. The dye-rich (x = 0.95) crystals show all the characteristic features of the brick-stone arrangement proposed for the molecular packing of the dye chromophores in J aggregates. The x = 0.3 phase boundary with a distinctly different crystal habit is stabilized by the areal match between the chromophore headgroups and the densely packed hydrocarbon chains. These thermodynamic and structural data are discussed in relation to the optical properties of the J-band aggregates.

• OSTI ID: 6751608
• Journal Information: Journal of Physical Chemistry; (USA), Vol. 93:11; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
36 MATERIALS SCIENCE
CYANINE DYES
PHASE STUDIES
STEARATES
DATA ANALYSIS
EXPERIMENTAL DATA
MEASURING INSTRUMENTS
MEASURING METHODS
OPTICAL PROPERTIES
SURFACE COATING
CARBOXYLIC ACID SALTS
DATA
DEPOSITION
DYES
INFORMATION
NUMERICAL DATA
PHYSICAL PROPERTIES
400201* - Chemical & Physicochemical Properties
360100 - Metals & Alloys
360600 - Other Materials
360602 - Other Materials- Structure & Phase Studies