Transformation diagrams for the collapse of a phospholipid monolayer.
Transformation diagrams for the collapse of a phospholipid monolayer.
复制标题
磷脂单层塌陷的转化图。
DOI：
10.1021/la049081t
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Hall,StephenB
中科院分区：
文献类型：
--
作者：
Rugonyi,Sandra;Smith,EthanC;Hall,StephenB
三维块体材料的相变动力学通常用相变图表示。时间-温度转变（TTT）和连续冷却转变（CCT）图绘制了通过冷却到转变温度以下将材料的特定部分转变为新相所需的时间。转变发生等温TTT图和连续冷却过程中通过一系列的温度CCT曲线。在这里，我们提出了类似的二维单分子膜的转换图，在平衡扩展压力（πe）崩溃，形成一个三维的体相。时间-表面压力-转换（TπT）图给出了当表面压力恒定时，特定部分的膜坍塌所需的时间，而连续压缩-转换图在表面压力连续变化时给出了相同的信息。图，这里从以前报道的1-棕榈酰-2-油酰磷脂酰胆碱的数据构建，提供了深入了解的电影的行为。TπT图成功地预测了薄膜压缩到高于π e的高表面压力的阈值速率的存在和近似大小以及不同界面压缩速率下获得的等温线的近似形状。图中还警告说，混合单分子层的行为，以前用成分变化解释，可能是由随表面压力变化的坍塌引起的。最后，TTT图和TπT图形状之间的相似性，即转化时间经过最小值，然后随着系统进一步偏离平衡而增加，这表明类似的机制决定了两个系统的行为。
The kinetics of phase transitions in three-dimensional bulk materials are commonly presented in transformation diagrams. Time−temperature transformation (TTT) and continuous-cooling-transformation (CCT) diagrams plot the time required to transform specific fractions of the material to the new phase by cooling below a transition temperature. Transformation occurs isothermally for the TTT diagrams and during continuous cooling through a range of temperatures for CCT curves. Here we present analogous transformation diagrams for two-dimensional monolayers, which collapse at the equilibrium spreading pressure (πe) to form a three-dimensional bulk phase. Time−surface pressure−transformation (TπT) diagrams give the time required for specific fractions of the film to collapse when surface pressure is constant, and continuous-compression-transformation diagrams give the same information when surface pressure varies continuously. The diagrams, constructed here from previously reported data for 1-palmitoyl-2-oleoyl phosphatidylcholine, provide insights into the behavior of the films. The TπT diagrams successfully predict the existence and approximate magnitude of a threshold rate for compressing the films to high surface pressures above πeand the approximate shape of isotherms obtained with different rates of interfacial compression. The diagrams also caution that the behavior of mixed monolayers, explained previously in terms of compositional changes, can instead result from collapse that varies with surface pressure.Finally, the similarity between the shapes of the TTT and TπT diagrams, with the time for transformation passing through a minimum and then increasing as the systems deviate further from equilibrium, suggests that analogous mechanisms determine the behavior of both systems.