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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 35, Number 6
BKCSDE 35(6)
June 20, 2014 

Role of Gel to Fluid Transition Temperatures of Polydiacetylene Vesicles with 10,12-Pentacosadiynoic Acid and Cholesterol in Their Thermochromisms
Jun Han Kwon, Ji Eun Song, Bora Yoon, Jong Man Kim, Eun Chul Cho*
Gel to fluid transition, Polydiacetylene vesicles, Colorimetric transition, Microcalorimetry thermograms
This study demonstrates gel-to-fluid transition temperatures of polydiacetylene bilayer vesicles could play important roles in their colorimetric transition temperatures. We prepared five types of polydiaceylene vesicles with 10,12-pentacosadiynoic acid (PCDA) and cholesterol (0–40 mol % of total content). From temperaturedependent observations of the optical signals (colors and UV-vis spectra), the blue-to-red colorimetric transition temperatures of polydiacetylene vesicles were decreased with the cholesterol contents. A further study with microcalorimetry and dynamic light scattering revealed that the polydiacetylene vesicles first underwent gel-to-fluid transitions, which were followed by event(s) responsible for the colorimetric transitions. Energies required for each event were quantified from analysis of the peaks in the microcalorimetry thermograms. The inclusion of cholesterol in the vesicles decreased both the gel-to-fluid and the colorimetric transition temperatures, suggesting that the colorimetric transition of the polydiacetylene vesicles was mediated by the former event although the event was not the direct reason for the color change.
1809 - 1816
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