Three-Dimensional Model for Planar Assembly of Triangular Molecules: Effect of Substrate–Molecule Interaction

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• 作者：A. IbenskasM. Šimėnas ; E. E. Tornau
• 刊名：Journal of Physical Chemistry C
• 出版年：2017
• 出版时间：February 16, 2017
• 年：2017
• 卷：121
• 期：6
• 页码：3469-3478
• 全文大小：608K
• ISSN：1932-7455

文摘

A three-dimensional (3D) model is proposed to study the self-assembly of triangular molecules at the solid–liquid interface and the effects of the surface–molecule interaction on molecular ordering. In our model the molecules are subject to the H-bond (e_H) and surface-molecule (e_s) interaction at the lowest plane (interface), while higher planes serve as an additional reservoir of molecules. To determine the ordering and adsorption properties, we study the temperature dependences of the specific heat C_V(T) at various values of e_s/e_H ratio. For low and intermediate values of e_s/e_H, in addition to the peak related to the ordering into the honeycomb phase at T_c, the low temperature C_V(T) peak (Schottky anomaly), caused by adsorption of molecules in the pores of the honeycomb structure, is found. For larger values of e_s/e_H the molecules are adsorbed on the entire first plane, and the adsorption-related peak of C_V(T) is found at higher temperature than the peak at T_c. For both e_s/e_H regimes the frustrated phase is obtained instead of the honeycomb phase at high molecular densities. At e_s/e_H < 2.3 the ordering temperature T_c strongly depends on the number of planes L_Z decreasing for e_s = 0 and L_Z → ∞ by 40% as compared to the 2D (L_Z = 1) model. For e_s/e_H ≳ 2.3 the ordering properties of the 3D model are equivalent to those of the 2D model.