4-butoxybenzylidene-4’-butylaniline (BBBA) Sıvı Kristalinin Geniş Sıcaklık Aralığında İncelenmesi: Optik, Dielektrik, Kalorimetrik ve Kızılötesi Spektroskopik Analiz

Bu çalışmada nematik ve farklı smektik mezofazlar sergileyen alkyloxy benzylidene alkylanilines sınıfına ait Schiff bazlı 4-butoxybenzylidene-4’-butylaniline (BBBA) sıvı kristalinin bazı fiziksel özellikleri incelenmiştir. Literatürde BBBA sıvı kristali üzerine çalışmalar oldukça az ve yetersizdir. Bu amaçla, morfolojik özelliklerinin belirlenmesi için optik tekstürleri mezofaz bölgelerinde ve faz geçiş bölgelerinde incelenmiştir. Optik tekstür analizlerinden BBBA’nın sergilediği mezofazlarda ortaya çıkan desenler belirlenmiştir. Ayrıca, dielektrik ölçümler ısıtma ve soğutma durumları için ayarı ayrı incelenerek her iki durum için dielektrik anizotropinin her bir mezofaz bölgesinde nasıl davrandığı araştırılmıştır. Yapılan araştırmalarda ısıtma ve soğutma durumlarında faz geçişler için termal histerezisin varlığı ortaya konulmuştur. Sıvı kristalik özellik sergilediği sıcaklık aralığında birçok mezofazın ortaya çıktığı BBBA’nın kızılötesi spektroskopik ölçümleri gerçekleştirilerek molekülün temel titreşim modları analiz edilmiştir. Ayrıca, BBBA’nın diferansiyel tarama kalorimetrisi yöntemi ile kalorimetrik ölçümleri hem ısıtma hem de soğutma durumları için yapılarak faz geçiş sıcaklıkları ve faz aralığı belirlenmiştir. Elde edilen kalorimetrik sonuçlar dielektrik ölçümlerden elde edilenler ile kıyaslanmıştır. Birçok mezofazı sergilemesi ve hakkında literatürde yeterince çalışmanın olmaması dolayısıyla BBBA sıvı kristali bilimsel araştırmalarda üzerine daha fazla araştırma yapılması gereken bir sıvı kristaldir.

Examination of 4-butoxybenzylidene-4'-butylaniline (BBBA) Liquid Crystal in Wide Temperature Range: Optical, Dielectric, Calorimetric and Infrared Spectroscopic Analysis

In this study, some physical properties of Schiff-based 4-butoxybenzylidene 4'-butylaniline (BBBA) liquid crystal belonging to alkyloxy benzylidene alkylanilines class with nematic and different smectic mesophase were investigated. Studies on BBBA liquid crystal are very few and insufficient in the literature. Due to this case, optical textures were examined in mesophase regions and phase transition regions to determine morphological properties. Patterns emerging in the mesophase exhibited by BBBA were determined from the optical texture analysis. In addition, the dielectric measurements were examined separately for heating and cooling conditions, and how the dielectric anisotropy behaves in each mesophase region for both cases. In the researches, the existence of thermal hysteresis for phase transitions in heating and cooling conditions has been revealed. The infrared spectroscopic measurements of the BBBA, in which many mesophases emerge in the temperature range in which it exhibits liquid crystalline properties, were performed and the fundamental vibration modes of the molecule were analyzed. In addition, the calorimetric measurements of the BBBA with the differential scanning calorimetry method were made for both heating and cooling conditions, and phase transition temperatures and phase range were determined. The calorimetric results obtained were compared with those obtained from dielectric measurements. The BBBA liquid crystal is a liquid crystal that needs more research in scientific research due to the fact that it exhibits many mesophase and there are not enough studies in the literature.

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