Molecular Arrangement Simulation of Pentacosadiynoic Acid Langmuir-Blodgett Films

Abstract

A simulation of the molecular arrangement of 10,12-pentacosadiynoic acid (PDA) Langmuir-Blodgett (LB) films has been carried out. The PDA molecules were optimized to local minimum energy structures by the molecular mechanics technique using Allinger's MM2 force field. The optimized molecules were arranged in the close-packed structures in a two-dimensional area where the closest atomic distances of the contacting molecules were restricted by the Van der Waals radii. The simulation results showed successful agreement with the reported experimental data.

Polymorph and Orientation Controls of Calcium Carbonate Crystals Achieved by Organic Matrices

“…Assuming trans-trans conformation for the two alkyl chains in a PDA molecule, monolayer thickness is calculated to be about 3.3 nm. 26 The film is most likely a trilayer, and the hydrocarbon side chains lie almost perpendicular to the film plane. Figure 2 a shows a TEM image of the polymerized PDA film transferred on a carbon micro grid instead of fused silica and the corresponding selected-area electron diffraction SAED pattern.…”