화학공학소재연구정보센터
Langmuir, Vol.19, No.4, 1390-1395, 2003
Phase behavior of liquid crystalline chitin/acrylic acid liquid mixture
Phase behavior of a liquid crystalline chitin/acrylic acid liquid mixture was studied to fabricate a chitin-based composite with unique optical property. From a series of phase separation studies, we can evaluate the ternary phase diagram of a chitin microfibril, water, and acrylic acid monomer system. A suitable starting liquid crystalline chitin concentration to obtain anisotropic monophase over a range of acrylic acid concentration (up to 33 (w/w) %) was 14.62% (14-15%) by weight. At lower acrylic acid concentration range, crystalline microfibrillar fragments of chitin self-assembled to form upper isotropic phase and lower anisotropic liquid crystal phase at high enough concentration of chitin crystallites. The latter showed a characteristic chiral nematic order, a fingerprint-like texture. Above this chitin concentration and at higher acrylic acid concentration range, the system formed a monophasic stable flow-birefringence glassy phase, which displayed a nematic order. This phase occurred within a very limited range of chitin crystallites concentration of about 6.22-6.41%, which provides a clear-cut boundary between isotropic phase and anisotropic phase as well as a metastable frozen-in state between chiral nematic order and nematic order.