Direct Observation of Diffuse Cone Behavior in de Vries Smectic-A and -C Phases of Organosiloxane Mesogens

被引：40

作者：

Yoon, HyungGuen ^{[1
]}

Agra-Kooijman, Dena M. ^{[1
]}

Ayub, Khurshid ^{[2
]}

Lemieux, Robert P. ^{[3
]}

Kumar, Satyendra ^{[1
]}

机构：

[1] Kent State Univ, Dept Phys, Kent, OH 44242 USA

[2] COMSATS Inst Informat Technol, Dept Chem, Abbottabad 22060, Pakistan

[3] Queens Univ, Dept Chem, Kingston, ON K7L 3N6, Canada

来源：

PHYSICAL REVIEW LETTERS | 2011年 / 106卷 / 08期

基金：

加拿大自然科学与工程研究理事会;

关键词：

RESOLUTION X-RAY; LIQUID-CRYSTALS; LAYER THICKNESS; TRANSITION; TILT;

D O I：

10.1103/PhysRevLett.106.087801

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

Simultaneous and direct x-ray measurements of the smectic layer spacing, molecular tilt, and orientational order in the de Vries smectic A (SmA) and C (SmC) phases of two organosiloxane mesogens reveal that (i) the SmC (tilt) order parameter exponent beta = 0.26 +/- 0.01 for 2nd order SmA-SmC transition-in excellent agreement with the tricritical behavior, (ii) the siloxane and hydrocarbon parts of the molecules are segregated and oriented parallel to the director with very different degree of orientational order, and (iii) thermal evolution of the effective molecular length is different in the two phases.

引用

页数：4

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