Topography and instability of monolayers near domain boundaries.
Topography and instability of monolayers near domain boundaries.
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域边界附近单分子层的形貌和不稳定性。
DOI：
10.1103/physreve.63.061602
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
K. Lee
中科院分区：
文献类型：
--
作者：
H. Diamant;T. Witten;C. Ege;A. Gopal;K. Lee
我们从理论上研究了在畴界附近的双相表面活性剂单分子层的形貌。两相的不同弹性性质通常导致“台面”的非平坦形貌，其中一相的域相对于另一相升高。台面陡峭但低，具有高达10 nm的高度。当单层被横向压缩时，台面形成悬突并最终在约K（deltac（0））（2）的表面张力下变得不稳定（deltac（0）是自发曲率的差，K是弯曲模量）。另外，当边界线张力小于Kdeltac（0）时，边界在压缩时会发生由地形引起的波纹不稳定性。扩散边界对这些功能和附近的临界点的地形行为的影响也进行了检查。我们讨论了我们的研究结果的相关性与几个实验观察相关的表面活性剂单分子膜：（一）最近发现的小地形特征域边界附近;（二）在混合磷脂单分子膜和模型肺表面活性剂中观察到的折叠行为;（三）粗糙化的域边界下看到的横向压缩;（四）在无张力表面活性剂膜的双相结构的情况下。
We theoretically study the topography of a biphasic surfactant monolayer in the vicinity of domain boundaries. The differing elastic properties of the two phases generally lead to a nonflat topography of "mesas," where domains of one phase are elevated with respect to the other phase. The mesas are steep but low, having heights of up to 10 nm. As the monolayer is laterally compressed, the mesas develop overhangs and eventually become unstable at a surface tension of about K(deltac(0))(2) (deltac(0) being the difference in spontaneous curvature and K a bending modulus). In addition, the boundary is found to undergo a topography-induced rippling instability upon compression, if its line tension is smaller than about Kdeltac(0). The effect of diffuse boundaries on these features and the topographic behavior near a critical point are also examined. We discuss the relevance of our findings to several experimental observations related to surfactant monolayers: (i) small topographic features recently found near domain boundaries; (ii) folding behavior observed in mixed phospholipid monolayers and model lung surfactants; (iii) roughening of domain boundaries seen under lateral compression; (iv) the absence of biphasic structures in tensionless surfactant films.