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Polymeric liquid crystals: cholesteric superstructure from blends of hydroxypropylcellulose esters
Author(s) -
Bianchi Estella,
Marsano Enrico,
Picasso Paolo,
Matassini Lorenzo,
Costa Camilla
Publication year - 2003
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.364
Subject(s) - miscibility , materials science , liquid crystal , isotropy , phase (matter) , helix (gastropod) , crystallography , absorption (acoustics) , superstructure , analytical chemistry (journal) , chemical engineering , thermodynamics , organic chemistry , optics , composite material , polymer , chemistry , ecology , physics , optoelectronics , snail , biology , engineering
n‐Butyric, iso‐butyric, n‐valeric and iso‐valeric esters of hydroxypropylcellulose were synthesized. Their behaviors, in terms of cholesteric structure, glass (T g ) and anisotropic‐isotropic (T i ) transition temperatures are compared to results in the literature. A 6–8 month time period from sample preparation has no influence on the cholesteric phase characteristics. Six binary blends may be formed from the four esters. They show only a T g value at each composition, which suggests a good miscibility among the components. However, positive deviation of linearity of T g vs. composition varies from one pair to another. Analysis of the absorption curves in UV‐vis spectra show that three pairs form a single cholesteric helix containing both components while other three give a only nematic phase. Colors changing from red to violet are shown for blends of n‐butyric and iso‐butyric esters at different weight ratio. Copyright © 2003 John Wiley & Sons, Ltd.