Premium
Atomistic Simulation of the Shape‐Memory Effect in Dry and Water Swollen Poly[( rac ‐lactide)‐ co ‐glycolide] and Copolyester Urethanes Thereof
Author(s) -
Ghobadi Ehsan,
Heuchel Matthias,
Kratz Karl,
Lendlein Andreas
Publication year - 2014
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.201300507
Subject(s) - copolyester , materials science , copolymer , lactide , swelling , polymer chemistry , glass transition , shape memory alloy , amorphous solid , hydrogen bond , intermolecular force , composite material , molecular dynamics , chemical engineering , molecule , polymer , chemistry , polyester , crystallography , computational chemistry , organic chemistry , engineering
An atomistic molecular dynamics simulation approach is applied to model the influence of urethane linker units as well as the addition of water molecules on the simulated shape‐memory properties of poly[( rac ‐lactide)‐ co ‐glycolide] (PLGA) and PLGA‐based copolyester urethanes comprising different urethane linkers. The shape‐memory performance of these amorphous packing models is explored in a simulated heating–deformation–cooling–heating procedure. Depending on the type of incorporated urethane linker, the mechanical properties of the dry copolyester urethanes are found to be significantly improved compared with PLGA, which can be attributed to the number of intermolecular hydrogen bonds between the urethane units. Good shape‐memory properties are observed for all the modeled systems. In the dry state, the shape fixation is found to be improved by implementation of urethane units. After swelling of the copolymer models with water, which results in a reduction of their glass transition temperatures, the relaxation kinetics during unloading and shape recovery are found to be substantially accelerated.