Microstructure of amphiphilic monodendrons at the air-water interface

Kirsten L. Genson, David Vaknin, Ovette Villacencio, Dominic V Mcgrath, Vladimir V. Tsukruk

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

Grazing incident X-ray diffraction and X-ray reflectivity have been performed on Langmuir monolayers of low generation monodendrons containing a crown-ether polar group, azobenzene spacer, and varying number of peripheral alkyl chains of 1, 2, 4, and 8. We observe that the cross-sectional mismatch between the bulky polar head and the alkyl tails has a profound effect on the local ordering of the alkyl tails. It is found that the alkyl chains in a single-tail molecule are significantly tilted away from the surface normal. The tilt is eliminated in molecules with two or more alkyl chains where the cross-sectional mismatch is in favor of the peripheral tails. The molecule with one tail possesses a supercell orthorhombic packing caused by structural nonequivalency on the neighboring tails. The two- and four-tail molecules form a mixed structure best described by a quasi-hexagonal unit cell, and the eight-tail molecule forms a more stable hexagonal unit cell. Peripheral tails for these molecules are in standing-off orientation. We suggest that the steric constraints cause lower correlations and a staggered packing structure of monolayers from the eight-tail molecule. We suggest that branching alkyl tails off the same phenyl ring and the presence of the phenyl rings in the vicinity of the branching are limiting factors on the chain packing at the air-water interface in monodendrons with multiple peripheral tails. We conclude that a significant portion of the molecules is submerged in the water subphase and possesses a "kink" shape.

Original languageEnglish (US)
Pages (from-to)11277-11284
Number of pages8
JournalJournal of Physical Chemistry B
Volume106
Issue number43
DOIs
StatePublished - Oct 31 2002

Fingerprint

microstructure
Microstructure
Molecules
Water
air
Air
water
molecules
Monolayers
Crown Ethers
Crown ethers
Azobenzene
monomolecular films
rings
grazing
cells
spacers
ethers
x rays
reflectance

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Cite this

Microstructure of amphiphilic monodendrons at the air-water interface. / Genson, Kirsten L.; Vaknin, David; Villacencio, Ovette; Mcgrath, Dominic V; Tsukruk, Vladimir V.

In: Journal of Physical Chemistry B, Vol. 106, No. 43, 31.10.2002, p. 11277-11284.

Research output: Contribution to journalArticle

Genson, KL, Vaknin, D, Villacencio, O, Mcgrath, DV & Tsukruk, VV 2002, 'Microstructure of amphiphilic monodendrons at the air-water interface', Journal of Physical Chemistry B, vol. 106, no. 43, pp. 11277-11284. https://doi.org/10.1021/jp026244i
Genson, Kirsten L. ; Vaknin, David ; Villacencio, Ovette ; Mcgrath, Dominic V ; Tsukruk, Vladimir V. / Microstructure of amphiphilic monodendrons at the air-water interface. In: Journal of Physical Chemistry B. 2002 ; Vol. 106, No. 43. pp. 11277-11284.
@article{96a7659c998541589bda017968a985f1,
title = "Microstructure of amphiphilic monodendrons at the air-water interface",
abstract = "Grazing incident X-ray diffraction and X-ray reflectivity have been performed on Langmuir monolayers of low generation monodendrons containing a crown-ether polar group, azobenzene spacer, and varying number of peripheral alkyl chains of 1, 2, 4, and 8. We observe that the cross-sectional mismatch between the bulky polar head and the alkyl tails has a profound effect on the local ordering of the alkyl tails. It is found that the alkyl chains in a single-tail molecule are significantly tilted away from the surface normal. The tilt is eliminated in molecules with two or more alkyl chains where the cross-sectional mismatch is in favor of the peripheral tails. The molecule with one tail possesses a supercell orthorhombic packing caused by structural nonequivalency on the neighboring tails. The two- and four-tail molecules form a mixed structure best described by a quasi-hexagonal unit cell, and the eight-tail molecule forms a more stable hexagonal unit cell. Peripheral tails for these molecules are in standing-off orientation. We suggest that the steric constraints cause lower correlations and a staggered packing structure of monolayers from the eight-tail molecule. We suggest that branching alkyl tails off the same phenyl ring and the presence of the phenyl rings in the vicinity of the branching are limiting factors on the chain packing at the air-water interface in monodendrons with multiple peripheral tails. We conclude that a significant portion of the molecules is submerged in the water subphase and possesses a {"}kink{"} shape.",
author = "Genson, {Kirsten L.} and David Vaknin and Ovette Villacencio and Mcgrath, {Dominic V} and Tsukruk, {Vladimir V.}",
year = "2002",
month = "10",
day = "31",
doi = "10.1021/jp026244i",
language = "English (US)",
volume = "106",
pages = "11277--11284",
journal = "Journal of Physical Chemistry B Materials",
issn = "1520-6106",
publisher = "American Chemical Society",
number = "43",

}

TY - JOUR

T1 - Microstructure of amphiphilic monodendrons at the air-water interface

AU - Genson, Kirsten L.

AU - Vaknin, David

AU - Villacencio, Ovette

AU - Mcgrath, Dominic V

AU - Tsukruk, Vladimir V.

PY - 2002/10/31

Y1 - 2002/10/31

N2 - Grazing incident X-ray diffraction and X-ray reflectivity have been performed on Langmuir monolayers of low generation monodendrons containing a crown-ether polar group, azobenzene spacer, and varying number of peripheral alkyl chains of 1, 2, 4, and 8. We observe that the cross-sectional mismatch between the bulky polar head and the alkyl tails has a profound effect on the local ordering of the alkyl tails. It is found that the alkyl chains in a single-tail molecule are significantly tilted away from the surface normal. The tilt is eliminated in molecules with two or more alkyl chains where the cross-sectional mismatch is in favor of the peripheral tails. The molecule with one tail possesses a supercell orthorhombic packing caused by structural nonequivalency on the neighboring tails. The two- and four-tail molecules form a mixed structure best described by a quasi-hexagonal unit cell, and the eight-tail molecule forms a more stable hexagonal unit cell. Peripheral tails for these molecules are in standing-off orientation. We suggest that the steric constraints cause lower correlations and a staggered packing structure of monolayers from the eight-tail molecule. We suggest that branching alkyl tails off the same phenyl ring and the presence of the phenyl rings in the vicinity of the branching are limiting factors on the chain packing at the air-water interface in monodendrons with multiple peripheral tails. We conclude that a significant portion of the molecules is submerged in the water subphase and possesses a "kink" shape.

AB - Grazing incident X-ray diffraction and X-ray reflectivity have been performed on Langmuir monolayers of low generation monodendrons containing a crown-ether polar group, azobenzene spacer, and varying number of peripheral alkyl chains of 1, 2, 4, and 8. We observe that the cross-sectional mismatch between the bulky polar head and the alkyl tails has a profound effect on the local ordering of the alkyl tails. It is found that the alkyl chains in a single-tail molecule are significantly tilted away from the surface normal. The tilt is eliminated in molecules with two or more alkyl chains where the cross-sectional mismatch is in favor of the peripheral tails. The molecule with one tail possesses a supercell orthorhombic packing caused by structural nonequivalency on the neighboring tails. The two- and four-tail molecules form a mixed structure best described by a quasi-hexagonal unit cell, and the eight-tail molecule forms a more stable hexagonal unit cell. Peripheral tails for these molecules are in standing-off orientation. We suggest that the steric constraints cause lower correlations and a staggered packing structure of monolayers from the eight-tail molecule. We suggest that branching alkyl tails off the same phenyl ring and the presence of the phenyl rings in the vicinity of the branching are limiting factors on the chain packing at the air-water interface in monodendrons with multiple peripheral tails. We conclude that a significant portion of the molecules is submerged in the water subphase and possesses a "kink" shape.

UR - http://www.scopus.com/inward/record.url?scp=0037206699&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0037206699&partnerID=8YFLogxK

U2 - 10.1021/jp026244i

DO - 10.1021/jp026244i

M3 - Article

AN - SCOPUS:0037206699

VL - 106

SP - 11277

EP - 11284

JO - Journal of Physical Chemistry B Materials

JF - Journal of Physical Chemistry B Materials

SN - 1520-6106

IS - 43

ER -