Optical characterization of a biaxial nematic between uniaxial nematic lyotropic phases. (3rd August 2021)

• Record Type: Journal Article
• Authors: Santos, O. R.; Braga, W. S.; Luders, D. D.; Sampaio, A. R.; Kimura, N. M.; Simões, M.; Palangana, A. J.
• Is Part Of: Phase transitions. Volume 94:Number 6/8(2021)
• Page Start: 546
• Page End: 555
• Publication Date: 2021-08-03
• Subjects: Liquid crystal -- biaxial nematic -- optical characterization -- optical conoscopy; 61.30.-v -- 42.65.Jx; Phase transformations (Statistical physics) -- Periodicals; 530.47405
• DOI: 10.1080/01411594.2021.1945598
• Languages: English
• ISSNs: 0141-1594

Abstract

ABSTRACT: The biaxial nematic ( N B ) phase bordered by two uniaxial nematic (discotic – N D and calamitic – N C ) phases and the one between N D phases are studied in potassium laurate ( KL ), decanol ( DeOH ) and D 2 O mixture using conoscopic images. The sequences of phases ( N D → N B + → N B − → N C and N D → N B + → N D ) were optically characterized, where N B + and N B − are the biaxial positive and biaxial negative nematic phases, respectively. A new sequence of phases ( N D → N B + → N B − → N B + → N D ) found in one line of the phase diagram positioned close to the interface with the N C phase was also optically confirmed through conoscopic images. The N B + ( N B − ) → N B − ( N B + ) transition point was determined by means of image processing. In this review work, we emphasize the relevance of the optical characterization of an N B − phase inherent to the nature of this lyotropic material.