The Effect of Acyl Chain Position on the 2D Monolayer Formation of Monoacyl-sn-Glycerol at the Air/Water Interface: Quantum Chemical Modeling

This paper deals with the results of quantum chemical modeling monoacyl-sn-glycerol 2D cluster formation at air/water interface using a semi-empirical PM3 method. The impact 2 or 3 positions acyl substituent on thermodynamics monolayer is assessed for surfactants an CnH2n+1COO chain length n = 6–17 carbon atoms. calculation shows significant change in spontaneous clusterization threshold isomeric compounds, which differs only position respect to glycerol backbone. almost equal shortening by approximately two methylene fragments. At same time, geometric parameters unit cell resulting monolayers are not affected so drastically. films question possess oblique orthorhombic and 3-monoacyl-sn-glycerol monolayers, as follows: 4.91 Å 4.82 b 5.00 4.92 Å, hydrocarbon chains tilted t 23.0° 23.5°. calculated accordance existing experimental data obtained grazing incidence X-ray diffraction measurements π-A isotherm technique.