Abstract
Aim: Multifunctional polymer-based biomaterials, which combine degradability with a shape-memory capability and in this way enable the design of actively moving implants such as self-anchoring implants or controlled release systems, have been recently introduced. Of particular interest are approved degradable polymers such as poly(L-lactide) (PLLA), which can be easily functionalized with a shape-memory effect. In the case of semicrystalline PLLA, the glass transition can be utilized as shape-memory switching domain.
Methods: In this work we applied a fully atomistic molecular dynamics simulation to study the shape-memory behavior of PLLA. A heating-deformation-cooling programming procedure was applied to atomistic PLLA packing models followed by a recovery module under stress-free conditions allowing the shape recovery. The recovery was simulated by heating the samples from Tlow = 250 K to Thigh = 500 K with different heating rates β of 125, 40 and 4 K⋅ns-1.
Results: We could demonstrate that the obtained strain recovery rate (Rr) was strongly influenced by the applied simulation time and heating rate, whereby Rr values in the range from 46% to 63% were achieved. On its own the application of a heating rate of 4 K⋅ns-1 enabled us to determine a characteristic switching temperature of Tsw = 473 K for the modeled samples.
Conclusions: We anticipate that the atomistic modeling approach presented should be capable of enabling further study of Tsw with respect to the molecular structure of the investigated SMP and therefore could be applied in the context of design and development of new shape-memory (bio)materials.
J Appl Biomater Funct Mater 2012; 10(3): 259 - 264
Article Type: ORIGINAL RESEARCH ARTICLE
DOI:10.5301/JABFM.2012.10440
Authors
Ehsan Ghobadi, Matthias Heuchel, Karl Kratz, Andreas Lendlein
Article History
- • Accepted on 28/09/2012
- • Available online on 19/12/2012
- • Published in print on 13/02/2013
This article is available as full text PDF.
Authors
- Ghobadi, Ehsan
[PubMed]
[Google Scholar]
Center for Biomaterial Development and Berlin-Brandenburg Centre for Regenerative Therapies, Institute of Polymer Research, Helmholtz-Zentrum Geesthacht, Teltow - Germany and Institute of Chemistry, University of Potsdam, Potsdam - Germany
- Heuchel, Matthias
[PubMed]
[Google Scholar]
Center for Biomaterial Development and Berlin-Brandenburg Centre for Regenerative Therapies, Institute of Polymer Research, Helmholtz-Zentrum Geesthacht, Teltow - Germany
- Kratz, Karl
[PubMed]
[Google Scholar]
Center for Biomaterial Development and Berlin-Brandenburg Centre for Regenerative Therapies, Institute of Polymer Research, Helmholtz-Zentrum Geesthacht, Teltow - Germany
- Lendlein, Andreas
[PubMed]
[Google Scholar]
Center for Biomaterial Development and Berlin-Brandenburg Centre for Regenerative Therapies, Institute of Polymer Research, Helmholtz-Zentrum Geesthacht, Teltow - Germany and Institute of Chemistry, University of Potsdam, Potsdam - Germany
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