Magnetic alignment of aqueous CTAB in nematic and hexagonal liquid crystalline phases investigated by spin-1 NMR

被引：27

作者：

Clawson, Jacalyn S. ^{[1
]}

Holland, Gregory P. ^{[1
]}

Alam, Todd M. ^{[1
]}

机构：

[1] Sandia Natl Labs, Dept Elect & Nanostructured Mat, Albuquerque, NM 87185 USA

来源：

PHYSICAL CHEMISTRY CHEMICAL PHYSICS | 2006年 / 8卷 / 22期

关键词：

D O I：

10.1039/b601539e

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Spin-1 NMR has been used to characterize the magnetically aligned neMatic and hexagonal liquid crystalline phases of aqueous cetyltrimethylammonium bromide (CTAB). A nematic/hexagonal biphasic region has been identified for the first time in this system. The nematic phase is characterized by an order parameter of smaller magnitude and greater temperature dependence. Magnetic alignment kinetic rates of the two phases differ greatly, with the nematic phase showing magnetic alignment much faster than the hexagonal phase. Equilibration has been monitored over time by measuring the change in quadrupole splitting as a function of temperature. As the sample equilibrates the temperature dependence of the splitting decreases logarithmically. This work also demonstrates how the phase and order of the liquid crystal can be manipulated during the early part of equilibration.

引用

页码：2635 / 2641

页数：7

共 34 条

[1]

Asaro F, 2001, CROAT CHEM ACTA, V74, P877

[2] X-RAY-DIFFRACTION STUDY OF MESOPHASES OF CETYLTRIMETHYLAMMONIUM BROMIDE IN WATER, FORMAMIDE, AND GLYCEROL [J].

AUVRAY, X ;

PETIPAS, C ;

ANTHORE, R ;

RICO, I ;

LATTES, A .

JOURNAL OF PHYSICAL CHEMISTRY, 1989, 93 (21) :7458-7464

[3] A NEW FAMILY OF MESOPOROUS MOLECULAR-SIEVES PREPARED WITH LIQUID-CRYSTAL TEMPLATES [J].

BECK, JS ;

VARTULI, JC ;

ROTH, WJ ;

LEONOWICZ, ME ;

KRESGE, CT ;

SCHMITT, KD ;

CHU, CTW ;

OLSON, DH ;

SHEPPARD, EW ;

MCCULLEN, SB ;

HIGGINS, JB ;

SCHLENKER, JL .

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1992, 114 (27) :10834-10843

[4] LINEAR AND NONLINEAR RHEOLOGICAL BEHAVIOR OF SALT-FREE AQUEOUS CTAB SOLUTIONS [J].

CAPPELAERE, E ;

CRESSELY, R ;

DECRUPPE, JP .

COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, 1995, 104 (2-3) :353-374

[5] STUDIES ON MESOPOROUS MATERIALS .2. SYNTHESIS MECHANISM OF MCM-41 [J].

CHEN, CY ;

BURKETT, SL ;

LI, HX ;

DAVIS, ME .

MICROPOROUS MATERIALS, 1993, 2 (01) :27-34

[6] Structural changes in CTAB/H2O mixtures using a rheological approach [J].

Coppola, L ;

Gianferri, R ;

Nicotera, I ;

Oliviero, C ;

Ranieri, GA .

PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 2004, 6 (09) :2364-2372

[7] QUADRUPOLAR ECHO DEUTERON MAGNETIC-RESONANCE SPECTROSCOPY IN ORDERED HYDROCARBON CHAINS [J].

DAVIS, JH ;

JEFFREY, KR ;

BLOOM, M ;

VALIC, MI ;

HIGGS, TP .

CHEMICAL PHYSICS LETTERS, 1976, 42 (02) :390-394

[8] AQUEOUS CETYL TRIMETHYLAMMONIUM BROMIDE SOLUTIONS [J].

EKWALL, P ;

MANDELL, L ;

SOLYOM, P .

JOURNAL OF COLLOID AND INTERFACE SCIENCE, 1971, 35 (04) :519-&

[9] A DEUTERIUM NUCLEAR-MAGNETIC-RESONANCE INVESTIGATION OF ORIENTATIONAL ORDER AND DIRECTOR KINETICS IN ARAMID SOLUTIONS [J].

FAN, SM ;

LUCKHURST, GR ;

PICKEN, SJ .

JOURNAL OF CHEMICAL PHYSICS, 1994, 101 (04) :3255-3267

[10] Magnetic-field-induced orientational ordering of alkaline lyotropic silicate - surfactant liquid crystals [J].

Firouzi, A ;

Schaefer, DJ ;

Tolbert, SH ;

Stucky, GD ;

Chmelka, BF .

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1997, 119 (40) :9466-9477

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