Synthesis of Novel Amphiphilic Azobenzenes and X-ray Scattering Studies of Their Langmuir Monolayers

Thomas Just Sørensen; Kristian Kjær; Dag Werner Breiby; Bo Wegge Laursen

doi:10.1021/la703022s

Synthesis of Novel Amphiphilic Azobenzenes and X-ray Scattering Studies of Their Langmuir Monolayers

Thomas Just Sørensen, Kristian Kjær, Dag Werner Breiby, Bo Wegge Laursen

Department of Chemistry

6 Citations (Scopus)

Abstract

We report a simple synthetic route to novel symmetrical alkylated and acylated amphiphilic 4,4‘-diaminoazobenzene dyes, with their optical axis perpendicular to the amphiphilic direction of the molecule. Three different substitution patterns are reported, two of which are highly amphiphilic. At the air-water interface, the amphiphilic azobenzenes form noncrystalline but stable Langmuir films that display an unusual reversible monolayer collapse close to 35 mN/m. The structures and phase transitions were studied by X-ray reflectivity (XR) and grazing-incidence X-ray diffraction, both utilizing synchrotron radiation. Compression beyond the collapse point does not change the XR data, showing that the film is unchanged at the molecular level, even at areas less than half of that of the collapse. This leads to the conclusion that few macroscopic collapse sites are responsible for reversibly removing large amounts of material from the interface.

Original language	English
Journal	Langmuir
Volume	24
Issue number	7
Pages (from-to)	3223–3227
Number of pages	4
ISSN	0743-7463
DOIs	https://doi.org/10.1021/la703022s
Publication status	Published - 2008

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title = "Synthesis of Novel Amphiphilic Azobenzenes and X-ray Scattering Studies of Their Langmuir Monolayers",

abstract = "We report a simple synthetic route to novel symmetrical alkylated and acylated amphiphilic 4,4{\textquoteleft}-diaminoazobenzene dyes, with their optical axis perpendicular to the amphiphilic direction of the molecule. Three different substitution patterns are reported, two of which are highly amphiphilic. At the air-water interface, the amphiphilic azobenzenes form noncrystalline but stable Langmuir films that display an unusual reversible monolayer collapse close to 35 mN/m. The structures and phase transitions were studied by X-ray reflectivity (XR) and grazing-incidence X-ray diffraction, both utilizing synchrotron radiation. Compression beyond the collapse point does not change the XR data, showing that the film is unchanged at the molecular level, even at areas less than half of that of the collapse. This leads to the conclusion that few macroscopic collapse sites are responsible for reversibly removing large amounts of material from the interface.",

author = "S{\o}rensen, {Thomas Just} and Kristian Kj{\ae}r and Breiby, {Dag Werner} and Laursen, {Bo Wegge}",

year = "2008",

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language = "English",

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T1 - Synthesis of Novel Amphiphilic Azobenzenes and X-ray Scattering Studies of Their Langmuir Monolayers

AU - Sørensen, Thomas Just

AU - Kjær, Kristian

AU - Breiby, Dag Werner

AU - Laursen, Bo Wegge

PY - 2008

Y1 - 2008

N2 - We report a simple synthetic route to novel symmetrical alkylated and acylated amphiphilic 4,4‘-diaminoazobenzene dyes, with their optical axis perpendicular to the amphiphilic direction of the molecule. Three different substitution patterns are reported, two of which are highly amphiphilic. At the air-water interface, the amphiphilic azobenzenes form noncrystalline but stable Langmuir films that display an unusual reversible monolayer collapse close to 35 mN/m. The structures and phase transitions were studied by X-ray reflectivity (XR) and grazing-incidence X-ray diffraction, both utilizing synchrotron radiation. Compression beyond the collapse point does not change the XR data, showing that the film is unchanged at the molecular level, even at areas less than half of that of the collapse. This leads to the conclusion that few macroscopic collapse sites are responsible for reversibly removing large amounts of material from the interface.

AB - We report a simple synthetic route to novel symmetrical alkylated and acylated amphiphilic 4,4‘-diaminoazobenzene dyes, with their optical axis perpendicular to the amphiphilic direction of the molecule. Three different substitution patterns are reported, two of which are highly amphiphilic. At the air-water interface, the amphiphilic azobenzenes form noncrystalline but stable Langmuir films that display an unusual reversible monolayer collapse close to 35 mN/m. The structures and phase transitions were studied by X-ray reflectivity (XR) and grazing-incidence X-ray diffraction, both utilizing synchrotron radiation. Compression beyond the collapse point does not change the XR data, showing that the film is unchanged at the molecular level, even at areas less than half of that of the collapse. This leads to the conclusion that few macroscopic collapse sites are responsible for reversibly removing large amounts of material from the interface.

U2 - 10.1021/la703022s

DO - 10.1021/la703022s

M3 - Journal article

SN - 0743-7463

VL - 24

SP - 3223

EP - 3227

JO - Langmuir

JF - Langmuir

IS - 7

ER -

Synthesis of Novel Amphiphilic Azobenzenes and X-ray Scattering Studies of Their Langmuir Monolayers

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