Volumetric, Ultrasonic, Spectroscopic, and Molecular Dynamics Simulations Studies of Molecular Interactions in Binary Mixtures of [Emim][NTf2] with 2-Propoxyethanol at Temperatures from 298.15 to 318.15 K

2020 ◽  
Vol 65 (7) ◽  
pp. 3566-3578
Author(s):  
Sowjanya Prathipati ◽  
Sreenivasa Rao Aangothu ◽  
Srinivasa Reddy Munnangi ◽  
Bala Murali Krishna Khandapu ◽  
Hari Babu Bollikolla
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Binary Mixtures ◽  
Molecular Interactions ◽  
Dynamics Simulations

Molecular Dynamics Simulations for Loading-Dependent Diffusion of CO2, SO2, CH4, and Their Binary Mixtures in ZIF-10: The Role of Hydrogen Bond

Langmuir ◽  
2017 ◽  
Vol 33 (42) ◽  
pp. 11543-11553 ◽  
Author(s):  
Li Li ◽  
Deshuai Yang ◽  
Trevor R. Fisher ◽  
Qi Qiao ◽  
Zhen Yang ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Hydrogen Bond ◽  
Molecular Dynamics Simulations ◽  
Binary Mixtures ◽  
Dynamics Simulations

scholarly journals Interface Characteristics of Neat Melts and Binary Mixtures of Polyethylenes from Atomistic Molecular Dynamics Simulations

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1059
Author(s):  
Sanghun Lee ◽  
Curtis W. Frank ◽  
Do Y. Yoon
Keyword(s):  
Molecular Dynamics ◽  
Surface Tension ◽  
Molecular Dynamics Simulations ◽  
Binary Mixtures ◽  
Surface Segregation ◽  
Surface Region ◽  
Polymer Chains ◽  
Methyl Groups ◽  
Free Standing ◽  
Dynamics Simulations

Molecular dynamics simulations of free-standing thin films of neat melts of polyethylene (PE) chains up to C150H302 and their binary mixtures with n-C13H28 are performed employing a united atom model. We estimate the surface tension values of PE melts from the atomic virial tensor over a range of temperatures, which are in good agreement with experimental results. Compared with short n-alkane systems, there is an enhanced surface segregation of methyl chain ends in longer PE chains. Moreover, the methyl groups become more segregated in the surface region with decreasing temperature, leading to the conclusion that the surface-segregation of methyl chain ends mainly arises from the enthalpic origin attributed to the lower cohesive energy density of terminal methyl groups. In the mixtures of two different chain lengths, the shorter chains are more likely to be found in the surface region, and this molecular segregation in moderately asymmetric mixtures in the chain length (C13H28 + C44H90) is dominated by the enthalpic effect of methyl chain ends. Such molecular segregation is further enhanced and dominated by the entropic effect of conformational constraints in the surface for the highly asymmetric mixtures containing long polymer chains (C13H28 + C150H3020). The estimated surface tension values of the mixtures are consistent with the observed molecular segregation characteristics. Despite this molecular segregation, the normalized density of methyl chain ends of the longer chain is more strongly enhanced, as compared with the all-segment density of the longer chain itself, in the surface region of melt mixtures. In addition, the molecular segregation results in higher order parameter of the shorter-chain segments at the surface and deeper persistence of surface-induced segmental order into the film for the longer chains, as compared with those in neat melt films.

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