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Calculation of phase diagrams not requiring the derivatives of the Gibbs energy demonstrated for a mixture of two homopolymers with the corresponding copolymer
Author(s) -
Horst Roland
Publication year - 1995
Publication title -
macromolecular theory and simulations
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.37
H-Index - 56
eISSN - 1521-3919
pISSN - 1022-1344
DOI - 10.1002/mats.1995.040040304
Subject(s) - copolymer , binodal , spinodal , phase diagram , thermodynamics , monomer , gibbs free energy , phase (matter) , ternary operation , materials science , chain (unit) , spinodal decomposition , polymer chemistry , mixing (physics) , chemistry , polymer , organic chemistry , physics , computer science , quantum mechanics , astronomy , programming language , composite material
A method is presented which allows the calculation of phase diagrams (spinodal, binodal and tie lines) on the basis of the Gibbs energy of mixing Δ G . No derivatives of Δ G with respect to the composition variables are required. This method is particularly useful in cases where the composition dependence of Δ G is very complex and no analytical representation of the derivatives can be given. The method is applied to a ternary mixture of two homopolymers with a copolymer consisting of the same monomers. The sequence distribution of the copolymer is kept constant between random and purely alternating, and phase diagrams are calculated for different chemical compositions of the copolymer. The complex phase separation behavior resulting for a 1 : 1 copolymer becomes much simpler as one monomeric unit starts to predominate in the copolymer.