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STUDY THE PROPERTIES OF THERMOTROPIC LIQUID CRYSTALS INDUCED BY HYDROGEN BONDING BETWEEN PYRIDYL- HETEROCYCLIC DERIVATIVES AND BENZOIC ACID, 4-HEPTYLOXYBENZOIC ACID OR 4-OCTYLOXYBENZOIC ACID

Author: Nasreen Raheem Jber
Journal: Al-Nahrain Journal of Science مجلة النهرين للعلوم ISSN: (print)26635453,(online)26635461 Year: 2010 Volume: 13 Issue: 4 Pages: 62-69
Publisher: Al-Nahrain University جامعة النهرين

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Abstract

Synthesis of new derivatives of heterocyclic compounds such as (Triazoles, tetrazole, oxazoleand thiadiazole). Liquid crystalline complexes have been obtained from binary mixtures of(4-pyridyl) heterocyclic derivatives with benzoic acid, 4-heptyloxychlorobenzoic acid or4-octyloxybenzoic acid. The (4-pyridyl) heterocyclic derivatives are not mesomorphic, but theH-bonded complexes are showed droplets nematic texture which is developed from threadednematic on slow heating. Their liquid crystalline properties were investigated by polarizing opticalmicroscopy.


Article
Theoretical Approach to Study Assembly Nature of Molecular Modeling System of Carbon Nanotube and a Nematic Liquid Crystal

Authors: Alaa Adnan Rashad --- Nasreen Raheem Jber --- Mehdi Salih Shihab
Journal: Al-Nahrain Journal of Science مجلة النهرين للعلوم ISSN: (print)26635453,(online)26635461 Year: 2012 Volume: 15 Issue: 4 Pages: 91-97
Publisher: Al-Nahrain University جامعة النهرين

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Abstract

Theoretical study for stable geometries of a nematic liquid crystal (LC) molecule assembled on the carbon nanotubes (CNT) wall by using semi-empirical molecular quantum calculations within the PM3 method as implemented in Hyperchem package. The interaction influence of ,-stacking between N-4`-Methoxybenzylidine-4-n-butylaniline (MBBA) liquid crystal molecule on the CNT wall led to formation of the local short range orientation order by LC molecules on the surface of the CNT due to the LC-CNT binding energy (,-stacking). The binding energy of the LC molecule on the CNT wall was within the typical van der Waals interaction. This binding originated from the electrostatic energy by a significant amount of charge transfer from the LC molecule to the CNT.

تمت الدراسة النظرية لاستقرارية الشكل الفراغي لجزيئات البلورات السائلة النيماتية (الخطية) المحتشدة على جدران الكاربون النانوتيوب, باستخدام حسابات ميكانيك الكم التجربية PM3 ضمن برنامج .Hyperchem وجد ان الاحتشاد ينتج من تأثير نوع (π,π ) بين جزيئات MBBA الكاربون النانوتيوب مؤدية الى تكوين طاقة الارتباط لمواقع قصيرة المدى تترتب فيها جزيئات البلورات السائلة ترتيبآ اتجاهيآ على جدار الانبوب النانوي.ان طبيعة التآثير المولد لطاقة الارتباط بين MBBA و CNT هي قوى فاندرفال و التي تنتج من التآثير الالكتروستاتيكي المتسبب من انتقال الشحنة من البلورات السائلة الى CNT .

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