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The generalized entropy theory (GET) offers many insights into how molecularparameters influence polymer glass-formation. Given the fact that chainrigidity often plays a critical role in understanding the glass-formation ofpolymer materials, the GET was originally developed based on models ofsemiflexible chains. Consequently, all previous calculations within the GETconsidered polymers with some degree of chain rigidity. Motivated by unexpectedresults from computer simulations of fully flexible polymer melts concerningthe dependence of thermodynamic and dynamic properties on the cohesiveinteraction strength ($\epsilon$), the present paper employs the GET to explorethe influence of $\epsilon$ on glass-formation in models of polymer melts witha vanishing bending rigidity, i.e., fully flexible polymer melts. In accordwith simulations, the GET for fully flexible polymer melts predicts that basicdimensionless thermodynamic properties (such as the thermal expansioncoefficient and isothermal compressibility) are universal functions of thetemperature scaled by $\epsilon$ in the regime of low pressures. Similarscaling behavior is also found for the configurational entropy density in theGET for fully flexible polymer melts. Moreover, we find that the characteristictemperatures of glass-formation increase linearly with $\epsilon$ and that thefragility is independent of $\epsilon$ in fully flexible polymer melts,predictions that are again consistent with simulations of glass-forming polymermelts composed of fully flexible chains. Beyond an explanation of these generaltrends observed in simulations, the GET for fully flexible polymer meltspredicts the presence of a positive residual configurational entropy at lowtemperatures, indicating a return to Arrhenius relaxation in the lowtemperature glassy state.

Generalized entropy theory of glass-formation in fully flexible polymer melts