TY  - JOUR
A1  - Fang, Liang
A1  - Gould, Oliver E. C.
A1  - Lysyakova, Liudmila
A1  - Jiang, Yi
A1  - Sauter, Tilman
A1  - Frank, Oliver
A1  - Becker, Tino
A1  - Schossig, Michael
A1  - Kratz, Karl
A1  - Lendlein, Andreas
T1  - Implementing and quantifying the shape-memory effect of single polymeric micro/nanowires with an atomic force microscope
JF  - ChemPhysChem : a European journal of chemical physics and physical chemistry
N2  - The implementation of shape-memory effects (SME) in polymeric micro- or nano-objects currently relies on the application of indirect macroscopic manipulation techniques, for example, stretchable molds or phantoms, to ensembles of small objects. Here, we introduce a method capable of the controlled manipulation and SME quantification of individual micro- and nano-objects in analogy to macroscopic thermomechanical test procedures. An atomic force microscope was utilized to address individual electro-spun poly(ether urethane) (PEU) micro- or nanowires freely suspended between two micropillars on a micro-structured silicon substrate. In this way, programming strains of 10 +/- 1% or 21 +/- 1% were realized, which could be successfully fixed. An almost complete restoration of the original free-suspended shape during heating confirmed the excellent shape-memory performance of the PEU wires. Apparent recovery stresses of sigma(max,app)=1.2 +/- 0.1 and 33.3 +/- 0.1MPa were obtained for a single microwire and nanowire, respectively. The universal AFM test platform described here enables the implementation and quantification of a thermomechanically induced function for individual polymeric micro- and nanosystems.
KW  - cyclic thermomechanical testing
KW  - atomic force microscopy
KW  - soft matter micro- and nanowires
KW  - shape-memory effect
KW  - materials science
Y1  - 2018
U6  - https://doi.org/10.1002/cphc.201701362
SN  - 1439-4235
SN  - 1439-7641
VL  - 19
IS  - 16
SP  - 2078
EP  - 2084
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - CHAP
A1  - Sauter, Tilman
A1  - Lützow, Karola
A1  - Schossig, Michael
A1  - Kosmella, Hans
A1  - Weigel, Thomas
A1  - Kratz, Karl
A1  - Lendlein, Andreas
T1  - Pore morphology as structural parameter to tailor the shape-memory effect of polyuetherurethane foams
T2  - Abstracts of papers : joint conference / The Chemical Institute of Cananda, CIC, American Chemical Society, ACS
Y1  - 2013
SN  - 0065-7727
VL  - 245
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Sauter, Tilman
A1  - Lützow, Karola
A1  - Schossig, Michael
A1  - Kosmella, Hans
A1  - Weigel, Thomas
A1  - Kratz, Karl
A1  - Lendlein, Andreas
T1  - Shape-memory properties of polyetherurethane foams prepared by thermally induced phase separation
JF  - Advanced engineering materials
N2  - In this study, we report the preparation of two structurally different shape-memory polymer foams by thermally induced phase separation (TIPS) from amorphous polyetherurethanes. Foams with either a homogeneous, monomodal, or with a hierarchically structured, bimodal, pore size distribution are obtained by adoption of the cooling protocol. The shape-memory properties have been investigated for both foam structures by cyclic, thermomechanical experiments, while the morphological changes on the micro scale (pore level) have been compared to the macro scale by an in situ micro compression device experiment. The results show that the hierarchically structured foam achieves higher shape-recovery rates and a higher total recovery as compared to the homogeneous foam, which is due to an increased energy storage capability by micro scale bending of the hierarchically structured foam compared to pure compression of the homogeneous foam.
Y1  - 2012
U6  - https://doi.org/10.1002/adem.201200127
SN  - 1438-1656
VL  - 14
IS  - 9
SP  - 818
EP  - 824
PB  - Wiley-VCH
CY  - Weinheim
ER  -