Elucidation of the effect of domain boundary on the mechanism of surface freezing phenomena

表面冻结（SF）是在温度Ts（比本体冻结温度Tb高几度）下在液体表面形成二维冷凝膜的现象。多伊奇等人曾指出，碳原子数为16~50的液态烷烃和碳原子数为10~28的液态烷醇都具有SF现象。本文利用表面张力法和X射线反射法，从成膜分子间相互作用的角度，探讨了碳氢化合物和氟碳化合物二元混合液表面分子的可吸附性，估算了表面组成和表面过剩热力学量，并测定了沿着表面法线的电子密度分布;（1）链长相差仅一个的同系烷烃和醇分子在表面几乎理想地混合;（2）具有氟碳链的杂化烷烃和烷醇在表面液层中形成凝聚相区;（2）在混合烷醇-杂化烷醇体系中，SF双层膜中的分子分布是不均匀的。

Surface freezing (SF) is the phenomenon of the two-dimensional condensed film formation at liquid surface at temperature Ts which is a few degrees above the bulk freezing temperature Tb. Deutsch et al. have claimed that liquid alkanes with 16~50 carbon atoms and alkanols with 10~28 ones exhibit SF phenomena. In this study, we aim at discussing the miscibility of molecules at the surface of the binary liquid mixture of hydrocarbon and fluorocarbon compounds from the viewpoint of the mutual interaction between the film forming molecules by surface tensiometry and X-ray reflection.The estimation of surface composition and surface excess thermodynamic quantity and the determination of electron density profile along surface normal indicated followings; (1) the homologous alkane and alcohol molecules with chain length difference by only one mix almost ideally at the surface, (2) hybrid alkane and alkanol with fluorocarbon chain form condensed phase domain in the surface liquid layer, and (2) the molecular distribution in the SF bilayer is heterogeneous in the mixed alkanol - hybrid alkanol system.