DETERMINATION OF THE IN-PLANE ELASTIC TENSOR OF CRYSTALLINE DECANOL MONOLAYERS ON WATER BY X-RAY DIFFRACTION
DETERMINATION OF THE IN-PLANE ELASTIC TENSOR OF CRYSTALLINE DECANOL MONOLAYERS ON WATER BY X-RAY DIFFRACTION
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通过 X 射线衍射测定水中结晶癸醇单分子层的面内弹性张量
DOI：
10.1103/physrevb.55.14163
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发表时间：
1997
影响因子：
3.7
通讯作者：
G. Grübel
中科院分区：
文献类型：
--
作者：
C. Zakri;A. Renault;J. Rieu;M. Vallade;B. Berge;J. Legrand;Guillaume Vignault;G. Grübel
我们展示了与表面张力测量相关的高分辨率X射线研究如何能够确定水-空气界面上结晶的1-癸醇单分子层的弹性常数。幂律衍射峰的形状和位置、屈服、剪切弹性常数和压缩弹性常数。在低温下，液体表面绕垂直轴的旋转扫描显示出六个尖锐的峰，证明了键取向长程有序的存在，正如六方二维(2D)晶体所预期的那样。根据Nelson-Halperin熔化理论，测得该材料的剪切弹性常数为(210\ifmmodePM\Else\TextPmFI30)mN/m，压缩弹性系数为(2500\ifmmodePm\Else\TextPmFI500)mN/m，这与二维固体的存在是一致的。在12℃到熔化温度之间，衍射线的急剧展宽既可以解释为六方相的出现，也可以解释为剪切模量值的大幅度降低，这与弱结晶理论的预期一致。
We show how high-resolution x-ray studies associated with surface tension measurements allow a determination of the elastic constants of crystalline 1-decanol monolayers at the water-air interface. The shape and position of the power-law diffraction peak yield, respectively, the shear and compression elastic constants. At low temperature, rotation scans of the liquid surface around a vertical axis exhibit six sharp peaks, proving the existence of the long-range order of bond orientations, as expected for a hexagonal two-dimensional (2D) crystal. We find a shear elastic constant of (210\ifmmode\pm\else\textpm\fi{}30) mN/m and a compression modulus of (2500\ifmmode\pm\else\textpm\fi{}500) mN/m. These values are compatible with the existence of a 2D solid, according to the Nelson-Halperin melting theory. Between \ensuremath{\sim}12 \ifmmode^\circ\else\textdegree\fi{}C and melting (${\mathrm{T}}_{\mathrm{m}}$=14.3 \ifmmode^\circ\else\textdegree\fi{}C), the drastic broadening of the diffraction line can be interpreted either as the occurrence of a hexatic phase or as a strong decrease of the shear modulus, as expected in the framework of the weak crystallization theory.