Molecular thermodynamic modeling of surface tension: Extension to molten polymers

Abstract

A combined molecular thermodynamic model with an equation of state was successfully extended for correlating the surface tension of 7 molten polymers. The model was coming from the combination of a statistical mechanical expression according to Fowler-Kirkwood-Buff approximation with the perturbed hard-sphere-chain equation of statistical association fluid theory by an attractive term of Yukawa tail. The systems under study were of homopolymers type including Poly(ethylene oxide), High-Density Poly(ethylene), Poly(dimethyl siloxane), Poly(vinyl methyl ether), Poly(ethylene glycol), Atactic-Poly(propylene glycol), and Isotactic-Poly(propylene glycol). The model also used the dipole moment of the monomer molecule of those systems as an adjustable coefficient. The model was able to correlate 65 surface tension data points of the above-mentioned polymers in 297–532.2 K range with the average absolute relative deviation (AARD) of 2.00%. In addition, a single layer neural network comprising two input parameters (temperature and soft-core diameter of Lennard-Jones fluid) and 11 neurons was applied to complete the research, achieving more than satisfactory results with the AARD of 0.88%.