scholarly journals Molecular dynamics study of isobaric and isochoric glass transitions in a model amorphous polymer

1999 ◽  
Vol 110 (14) ◽  
pp. 7058-7069 ◽  
Author(s):  
Liu Yang ◽  
David J. Srolovitz ◽  
Albert F. Yee
Keyword(s):  
Molecular Dynamics ◽  
Amorphous Polymer ◽  
Glass Transitions

Structure and Mechanical Properties of Rubberlike Proteins in Animals

1987 ◽  
Vol 60 (3) ◽  
pp. 417-438 ◽  
Author(s):  
John M. Gosline
Keyword(s):  
Amorphous Polymer ◽  
Polymer Networks ◽  
Random Coil ◽  
Future Research ◽  
Random Networks ◽  
Glass Transitions ◽  
Mechanical State ◽  
Protein Molecules ◽  
Polypeptide Chains ◽  
Covalent Crosslinks

Abstract Polymer networks formed from protein molecules that adopt kinetically-free, random-coil conformations are found in many animals, where they play a number of important roles. The 5 rubberlike proteins isolated and studied to date indicate that animal rubbers, like their synthetic counterparts, contain random networks which are usually stabilized by covalent crosslinks. Long-range elasticity in rubberlike proteins is based on changes in the conformational entropy of random-coil molecules. Further, these protein networks show viscoelastic glass transitions similar to all other amorphous polymer networks. Future research on protein sequences should increase our understanding of how polypeptide chains can function as random-coil molecules, and studies into the mechanical state of elastin in arterial tissues may provide important clues about the mechanisms of some forms of human disease.

Molecular dynamics simulations of the scratch test on linear amorphous polymer surfaces: A study of the local friction coefficient

Wear ◽  
2011 ◽  
Vol 271 (11-12) ◽  
pp. 2751-2758 ◽  
Author(s):  
M. Solar ◽  
H. Meyer ◽  
C. Gauthier ◽  
O. Benzerara ◽  
R. Schirrer ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Friction Coefficient ◽  
Molecular Dynamics Simulations ◽  
Amorphous Polymer ◽  
Scratch Test ◽  
Polymer Surfaces ◽  
Dynamics Simulations

Computer Studies on free and Confined Amorphous Polymer Films

1996 ◽  
Vol 464 ◽  
Author(s):  
G. Pätzold ◽  
D.W. Heermann ◽  
A. Linke ◽  
T. Hapke
Keyword(s):  
Molecular Dynamics ◽  
Preparation Method ◽  
Amorphous Polymer ◽  
Surface Preparation ◽  
Van Der Waals Interactions ◽  
Pressure Oscillations ◽  
Free Surfaces ◽  
Polymer Systems ◽  
Pressure Profiles ◽  
Computer Studies

ABSTRACTWe study surface effects in amorphous polymer systems by means of computer simulation. In the framework of molecular dynamics, we present two different methods to prepare such surfaces. Free surfaces are stabilized solely by van-der-Waals interactions, whereas confined surfaces emerge in the presence of repelling plates. The buildup of density and pressure profiles from zero to their bulk values depends on the surface preparation method. In the case of confined surfaces, we find density and pressure oscillations next to the repelling plates. For free surfaces, we attest chain-end enrichment and present a comparison between density profile and particle coordination number.

MOLECULAR DYNAMICS SIMULATIONS OF LIQUID CRYSTAL ANCHORING AT AN AMORPHOUS POLYMER SURFACE

1999 ◽  
Vol 10 (02n03) ◽  
pp. 415-429 ◽  
Author(s):  
T. P. DOERR ◽  
P. L. TAYLOR
Keyword(s):  
Molecular Dynamics ◽  
Liquid Crystal ◽  
Force Field ◽  
Molecular Dynamics Simulations ◽  
Amorphous Polymer ◽  
Polymer Surface ◽  
The Other ◽  
Substantial Fraction ◽  
Dynamics Simulations ◽  
First Time

Atomistic molecular dynamics simulations have been used, apparently for the first time, to investigate the anchoring behavior of a liquid crystal at the interface with an amorphous polymer. The simulations studied a system consisting of the nematogen 5CB at the surface of amorphous polyethylene, and used the simple Dreiding II force field. The simulations indicate a preference for nonplanar anchoring. Two distinct microscopic paths have been identified by which the liquid crystal changes orientation at the surface. In one case, only one or a few of the 5CB molecules are rotating at any particular time. In the other case, a substantial fraction of the molecules rotate simultaneously.

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