Thermodynamics of polymeric liquids: Simple fluids with entropic elasticity obeying the time-temperature superposition principle

Abstract

Polymeric liquids are considered to be simple fluids displaying two properties: i) they obey the time-temperature superposition (TTS) principle, and ii) are endowed with entropic elasticity. An analysis is performed of existing theories which consider the above properties separately. Non-trivial compatibility conditions are found, which require appreciable modifications of the formulation byCrochet andNaghdi of the TTS principle. The thermodynamic equations of state of fluids which obey the TTS principle and have a configurational entropy are then formulated and discussed.