Conformational characteristics and configurational properties of poly(ethylene oxide-alt-ethylene sulfide)

Conformational analysis of poly(ethylene oxide-alt-ethylene sulfide) (PEOES) has been carried out by ab initio molecular orbital (MO) calculations for a model compound, 2-methoxyethyl methyl sulfide (MEMS), and a refined rotational isomeric state (RIS) scheme developed here. The refined RIS scheme, including the dependence of geometrical parameters as well as interaction energies on conformations of the current and neighboring bonds, is formulated herein. Experimental observations of bond conformations of MEMS and the dipole moment ratio and its temperature coefficient of PEOES in benzene were exactly reproduced by the completely theoretical treatment of the MO-RIS calculations. Thermodynamic and solution properties and weak interactions of PEOES are discussed and compared with those of poly(ethylene oxide) and poly(ethylene sulfide).