ISSN:
1435-1536
Keywords:
Lyotropic liquid crystals
;
phase transitions
;
photoisomerization
;
solubilization
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Clearing temperaturesT HI, as observed in phase transitions from the hexgonal lyotropic liquid crystalline phase to the isotropic micellar phase of aqueous potassium octanoate systems were found to be sensitive to the presence of small amounts of certain stilbene derivatives. The influence onT HI is specific for the stilbene derivative and depends on whether thecis ortrans form is present. Sincetrans andcis isomers can be interconverted photochemically, phases can be switchedin situ upon exposure to light. Eight derivatives of stilbene were tested: 4-hydroxystilbene, 4-potassium-stilbenolate, 3− and 4-carboxystilbene, 3- and 4-potassium stilbene carboxylate, 2′,5′-dimethoxy-4-aminostilbene, and 4,4′-diaminostilbene-2,2′-disulfonic acid. Upon solubilizing ≤1% w/w of trans stilbenes the clearing points varied between +15.5 K to −12 K as compared to pure aqueous potassium octanoate. Photoisomerization to the cis form resulted in increases ofT HI by up to 7.5 K.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00654751
