Relaxation process and dynamic heat capacity at the main transition of multi-lamellar vesicles of phosphatidylcholines

在研究的第一阶段，对不同烷基链长的单层血管样品进行了研究。对于链长从12到15的测量，发现伴随相变的热反常显著地依赖于链长。研究还发现，链长为12的单层样品与链长相同的多层样品具有相似的中间相。对这些结果的详细分析表明，观测到的异常的链长依赖关系可以用修正的Izuyama-Akutsu理论来描述，该理论解释了热异常的囊泡大小依赖关系。根据这个修正的理论，我们可以通过调整囊泡大小和链长来达到临界点。我们发现直径为30 nm、链长为15的样品接近临界点。初步分析表明，临界指数α=0.5-0.7。更详细的分析正在进行中。尽管对多层囊泡的测量落后于计划，但上述关于单层囊泡的结果为今后对单层和多层囊泡的研究提供了一个很好的背景。

At the first stage of the research, the unilamellar vasicle samples with various alkyl chain length have been studied. For the measurements with chain length from 12 to 15, it was found that the heat anomaly accompanying the transition depends significantly on the chain length. It was also found that the unilamellar sample with chain length 12 shows an intermediate phase, which is similar to the multilamellar sample with the same chain length. A detailed analysis of these results has revealed that the observed chain-length dependence of the anomaly can be described with the modified Izuyama-Akutsu theory which has been proposed by the present authors to explain the vesicle-size dependence of the heat anomaly. It is expected from this modified theory that we can reach a critical point by adjusting the vesicle size and the chain length. We found that the sample with 30 nm diameter with chain length 15 is close to the critical point. A preliminary analysis shows that the critical exponent has a value alpha=0.5-0.7. More detailed analyzes are in progress. Although the measurement on multilamellar vesicles is behind the schedule, the results on unimalellar vesicles described above serve as a good background for future studies both on unilamellar and multilamellar vesicles.