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Simulating the Shape‐Memory Behavior of Amorphous Switching Domains of Poly( L ‐lactide) by Molecular Dynamics
Author(s) -
Ghobadi Ehsan,
Heuchel Matthias,
Kratz Karl,
Lendlein Andreas
Publication year - 2013
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201200450
Subject(s) - amorphous solid , molecular dynamics , shape memory polymer , materials science , dihedral angle , deformation (meteorology) , shape memory alloy , composite material , polymer , crystallography , molecule , chemistry , computational chemistry , hydrogen bond , organic chemistry
The thermally induced shape‐memory effect of polymers is typically characterized by cyclic uniaxial thermomechanical tests. Here, a molecular‐dynamics (MD) simulation approach of such a cyclic uniaxial thermomechanical test is presented for amorphous switching domains of poly( L ‐lactide) (PLLA). Uniaxial deformation of the constructed PLLA models is simulated with a Parinello–Rahman scheme, as well as a pragmatic geometrical approach. We are able to describe two subsequent test cycles using the presented simulation approach. The obtained simulated shape‐memory properties in both test cycles are similar and independent of the applied deformation protocols. The simulated PLLA shows high shape fixity ratios ( R f ≥ 94%), but only a moderate shape recovery ratio is obtained ( R r ≥ 30%). Finally, the structural changes during the simulated test are characterized by analysis of the changes in the dihedral angle distributions.