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Y-H TİPİ SIVI KRİSTAL SİSTEMLERE KARBON NANOTÜP İLAVESİNİN MOLEKÜLER YÖNLENME VE FAZ GEÇİŞİ ÜZERİNE ETKİLERİ

EFFECTS ON MOLECULAR ORIENTATION AND PHASE TRANSITION OF ADDITION OF CARBON NANOTUBES INTO G-H LIQUID CRYSTAL SYSTEMS

Journal Name:

  • Gazi Üniversitesi Mühendislik-Mimarlık Fakültesi Dergisi

Publication Year:

  • 2011

Key Words:

Keywords (Original Language):

Author NameUniversity of AuthorFaculty of Author
Abstract (2. Language): 
Especially with applications in display technology, liquid crystals have become the focus of great interest in recent years. Guest-host liquid crystal displays (GH-LCDs) are widely used because of their wide viewing angle, lower costs, excellent hues and high brightness levels. The aim of this study is to improve the molecular orientation and to examine effects on the nematic-isotropic phase transition temperature of dyes having different molecular structure and single walled carbon nanotubes used in GH-LCDs. For this purpose, three different dyes were separately doped to two different nematic liquid crystals and, their order parameters and phase transition temperatures were determined. At the second stage, single walled carbon nanotubes in different amounts were added to each of these solutions and the experiments were repeated as similar to previous ones. Although the order parameter had different values depending on dye, its maximal value was attained with anthraquinone structured dye. Addition of carbon nanotubes gave rise to different effects for each case. The dyes and nanotube did not significantly destabilize the mesomorphic phase of nematic hosts because the change in phase transition temperature stayed within limitations required.
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Abstract (Original Language): 
Özellikle görüntü teknolojisindeki uygulamaları ile sıvı kristaller son yıllarda büyük ilgi odağı haline gelmiştir. Yolcu-Hancı (Y-H) tipi sıvı kristal göstergeler geniş görüş açısı, düşük maliyet, mükemmel renk tonu ve yüksek parlaklıkları sebebiyle yaygın bir şekilde kullanılmaktadırlar. Bu çalışmanın amacı, Y-H tipi sistemlerde farklı moleküler yapıda boyalar ile tek duvarlı karbon nanotüp kullanarak moleküler yönlenmeyi geliştirmek ve nematik-izotropik faz geçiş sıcaklığı üzerine etkilerini incelemektir. Bu amaçla farklı kimyasal yapıdaki üç boyarmadde, farklı bileşimdeki iki nematik sıvı kristale ayrı ayrı eklenerek düzen parametreleri ve faz geçiş sıcaklıkları belirlenmiştir. Bir sonraki aşamada bu karışımların her birine iki farklı oranda tek duvarlı karbon nanotüp ilave edilmiş ve deneyler tekrarlanmıştır. Sonuç olarak sıvı kristal için düzen parametresi, boyaya bağlı olarak farklı değerler almakla birlikte en yüksek değerini antrakinon yapılı boyada bulmuş; karbon nanotüp ilavesi farklı etkilere sebep olmuştur. Katkılı sıvı kristallerin nematik-izotropik faz geçiş sıcaklığındaki değişim, katkısız hale kıyasla kabul edilebilir sınırlar içerisinde kaldığından, sıvı kristal fazın kararlılığı üzerine olumsuz etkilerinin olmadığı sonucuna varılmıştır.
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