scholarly journals Shape-Memory Nanofiber Meshes with Programmable Cell Orientation

Fibers ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 20 ◽  
Author(s):  
Eri Niiyama ◽  
Kanta Tanabe ◽  
Koichiro Uto ◽  
Akihiko Kikuchi ◽  
Mitsuhiro Ebara
Keyword(s):  
Mechanical Properties ◽  
Shape Memory ◽  
Rational Design ◽  
Control Cell ◽  
Hexamethylene Diisocyanate ◽  
Molar Ratio ◽  
Great Promise ◽  
Original Structure ◽  
Cell Alignment ◽  
Shape Memory Properties

In this work we report the rational design of temperature-responsive nanofiber meshes with shape-memory properties. Meshes were fabricated by electrospinning poly(ε-caprolactone) (PCL)-based polyurethane with varying ratios of soft (PCL diol) and hard [hexamethylene diisocyanate (HDI)/1,4-butanediol (BD)] segments. By altering the PCL diol:HDI:BD molar ratio both shape-memory properties and mechanical properties could be readily turned and modulated. Though mechanical properties improved by increasing the hard to soft segment ratio, optimal shape-memory properties were obtained using a PCL/HDI/BD molar ratio of 1:4:3. Microscopically, the original nanofibrous structure could be deformed into and maintained in a temporary shape and later recover its original structure upon reheating. Even when deformed by 400%, a recovery rate of >89% was observed. Implementation of these shape memory nanofiber meshes as cell culture platforms revealed the unique ability to alter human mesenchymal stem cell alignment and orientation. Due to their biocompatible nature, temperature-responsivity, and ability to control cell alignment, we believe that these meshes may demonstrate great promise as biomedical applications.

scholarly journals Shape-memory Nanofiber Meshes with Programmable Cell Orientation

2018 ◽  
Author(s):  
Eri Niiyam ◽  
Kanta Tanabe ◽  
Koichiro Uto ◽  
Akihiko Kikuchi ◽  
Mitsuhiro Ebara
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Rational Design ◽  
Hexamethylene Diisocyanate ◽  
Molar Ratio ◽  
Original Structure ◽  
Cell Functions ◽  
Shape Memory Properties ◽  
Hard Segments

This paper reports a rational design of temperature-responsive nanofiber meshes with shape-memory effect. The meshes were fabricated by electrospinning a poly(ε-caprolactone) (PCL)-based polyurethane with different contents of soft and hard segments. The effects of PCL diol/hexamethylene diisocyanate (HDI)/1,4-butanediol (BD) molar ratio in terms of the contents of soft and hard segments on the shape-memory properties were investigated. Although the mechanical property improved with increasing hard segment ratio, optimal shape-memory properties were obtained with a PCL/HDI/BD molar ratio of 1:4:3. At a microscopic level, the original nanofibrous structure was easily deformed into a temporary shape, and recovered its original structure when the sample was reheated. A higher recovery rate (>89%) was achieved even when the mesh was deformed up to 400%. Finally, the nanofiber meshes were used to control the alignment of human mesenchymal stem cells (hMSCs). The hMSCs aligned well along the fiber orientation. The proposed nanofibrous meshes with the shape-memory effect have the potential to serve as in vitro platforms for the investigation of cell functions as well as implantable scaffolds for wound-healing applications.

scholarly journals Shape Memory Behavior of Carbon Black-reinforced Trans-1,4-polyisoprene and Low-density Polyethylene Composites

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 807 ◽  
Author(s):  
Lin Xia ◽  
Han Gao ◽  
Weina Bi ◽  
Wenxin Fu ◽  
Guixue Qiu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
Shape Memory ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Shape Memory Behavior ◽  
Blending Method ◽  
Shape Memory Properties ◽  
Shape Memory Composites ◽  
Properties Of Composites

Shape memory composites of trans-1,4-polyisoprene (TPI) and low-density polyethylene (LDPE) with easily achievable transition temperatures were prepared by a simple physical blending method. Carbon black (CB) was introduced to improve the mechanical properties of the TPI/LDPE composites. The mechanical, cure, thermal and shape memory properties of the TPI/LDPE/CB composites were investigated in this study. In these composites, the crosslinked network generated in both the TPI and LDPE portions acted as a fixed domain, while the crystalline regions of the TPI and LDPE portions acted as a reversible domain in shape memory behavior. We found the mechanical properties of composites were promoted significantly with an increase of CB content, accompanied with the deterioration of shape memory properties of composites. When CB dosage was 5 parts per hundred of rubber composites (phr), best shape memory property of composites was obtained with a shape fixity ratio of 95.1% and a shape recovery ratio of 95.0%.

Effect of Tin Addition on Shape Memory Effect and Mechanical Properties of Cu-Al-Ni Shape Memory Alloy

2020 ◽  
Vol 38 (8A) ◽  
pp. 1178-1186
Author(s):  
Raad S. Ahmed Adnan
Keyword(s):  
Mechanical Properties ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Transformation Temperature ◽  
Mechanical Test ◽  
Hardness Test ◽  
Micro Hardness ◽  
Recovery Strain ◽  
Shape Memory Properties

This study examines the effect of Sn additions on Cu-14%Al-4.5%Ni shape memory alloy. Sn was added in three different percentages (0.3,1,3) %. The alloys were mechanically tested both in compression test and micro hardness test. Also, a thermo-mechanical test was performed on the alloys. Results showed an increase in the transformation temperature outside the domain and also a better recovery strain with the increase of Sn percentage of 3% Sn addition showed the best results in mechanical properties while the 3% Sn showed a better Shape Memory Properties near to super elastic.

Development of zwitterionic polyurethanes with multi-shape memory effects and self-healing properties

2015 ◽  
Vol 3 (6) ◽  
pp. 2924-2933 ◽  
Author(s):  
Shaojun Chen ◽  
Funian Mo ◽  
Yan Yang ◽  
Florian J. Stadler ◽  
Shiguo Chen ◽  
...  
Keyword(s):  
Shape Memory ◽  
Memory Effects ◽  
Hexamethylene Diisocyanate ◽  
Self Healing ◽  
Shape Memory Properties ◽  
Shape Memory Effects

Novel zwitterionic polyurethanes containing sulfobetaines, featuring excellent multi-shape-memory properties and self-healing properties, are prepared from N-methyldiethanolamine, hexamethylene diisocyanate and 1,3-propanesultone.

Synthesis and Characterization of IPDI Based Shape Memory Polyurethane

2020 ◽  
Vol 1010 ◽  
pp. 142-147
Author(s):  
Nur Athirah Rasli @ Rosli ◽  
Syazana Ahmad Zubir
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Soft Segment ◽  
Shape Memory Polymer ◽  
Palm Kernel ◽  
Hexamethylene Diisocyanate ◽  
Molar Ratio ◽  
Scanning Calorimetry ◽  
Chain Flexibility

Various polyurethane-based shape memory polymer was synthesized using polycaprolactone (PCL) as soft segment and, hexamethylene diisocyanate (HMDI) and isophorone diisocyanate (IPDI) as the hard segments. Palm kernel oil-based polyol was used to replace part of the petroleum-based polyol due to the increasing demand on renewable resources as a result of environmental awareness. The synthesis has been carried out using two step polymerization method. The effects of varying the molar ratio of IPDI/HMDI on material properties such as crystallinity, transition temperature, morphology, shape memory effect and tensile strength were investigated by using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), shape memory test and tensile test. A high IPDI content in SMPU results in better shape memory effect, whereas increasing HMDI content leads to a better chain flexibility. In this work, the incorporation of IPDI contributes to the formation of phase separation which enhance the formation of crystalline soft segment structure while the incorporation of HMDI as isocyanate tend to promote phase mixing which enhance the chain flexibility of the SMPU backbone.

Hierarchical porous carbon nanofibrous membranes with an enhanced shape memory property for effective adsorption of proteins

RSC Advances ◽  
2015 ◽  
Vol 5 (79) ◽  
pp. 64318-64325 ◽  
Author(s):  
Gang Fan ◽  
Jianlong Ge ◽  
Hak-Yong Kim ◽  
Bin Ding ◽  
Salem S. Al-Deyab ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shape Memory ◽  
Protein Adsorption ◽  
Porous Carbon ◽  
Hierarchical Porous Carbon ◽  
Shape Memory Property ◽  
Memory Property ◽  
Adsorption Performance ◽  
Hierarchical Porous ◽  
Shape Memory Properties

A hierarchical porous CNF membrane with robust mechanical properties, exhibiting intriguing shape memory properties and efficient protein adsorption performance.

Synthesis and Characterization of a Bio-Compatible Shape Memory Polymer Blend for Biomedical and Clinical Applications

2014 ◽  
Author(s):  
Janice J. Song ◽  
Jennifer Kowalski ◽  
Hani E. Naguib
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Shape Memory ◽  
Recovery Rate ◽  
Shape Recovery ◽  
Clinical Applications ◽  
Poly Lactic Acid ◽  
Shape Memory Properties ◽  
Shape Fixity ◽  
Recovery Temperature

Shape memory polymers (SMP) are a class of stimuli-responsive materials that are able to respond to external stimulus such as heat by altering their shape. Bio-compatible SMPs have a number of advantages over existing SMP materials and are being studied extensively for biomedical and clinical applications. Polymer blending has proved to be an effective method to improve the mechanical properties of polymers (such as tensile strength and toughness) as well as shape memory properties. In this study, we investigate the effect of blending two bio compatible polymers, thermoplastic polyurethane (TPU), a polymer with a high toughness and percent elongation, and poly-lactic acid (PLA), a stiff and strong polymer. The thermal, mechanical and thermo-mechanical (shape memory) properties of TPU/PLA blends were characterized in the following weight percent compositions: 80/20, 65/35, and 50/50 TPU/PLA. The TPU/PLA SMP blending was achieved with melt-blending and the tensile samples were fabricated with compression molding. The mechanical properties of each blend were studied at three different temperatures. The following thermo-mechanical (or shape memory) properties were also studied at each temperature: the shape fixity rate (Rf), shape recovery rate (Rr) and the effect of recovery temperature on the shape memory behavior. The microstructure of the polymer blends were investigated with an environmental scanning electron microscope (SEM). The results showed that the glass transition temperatures of the blends were similar to pure PLA. The toughness of the SMP blend increased with increasing TPU concentration and the tensile strength of the blend increased with PLA composition. The shape fixity rate of the TPU/PLA blend increased with increasing TPU content and the shape recovery rate increased with increasing deformation and recovery temperature. The various TPU/PLA SMP blends characterized in this study have the potential to be developed further for specific biomedical and clinical applications.

Stress-induced Bimodal Ordering in POSS/PCL Biodegradable Shape Memory Nanocomposites

2012 ◽  
Vol 1450 ◽  
Author(s):  
Bonifacio Alvarado-Tenorio ◽  
Angel Romo-Uribe ◽  
Patrick T. Mather
Keyword(s):  
Shape Memory ◽  
Network Architecture ◽  
Crosslink Density ◽  
Room Temperature ◽  
Molar Ratio ◽  
Saxs Data ◽  
X Ray ◽  
X Ray Scattering ◽  
Shape Memory Properties ◽  
Induced Crystallization

ABSTRACTSimultaneous wide- and small- angle X-ray scattering (WAXS-SAXS) has revealed a stress-induced bimodal orientation of POSS crystals and PCL chains, both in a constrained POSS/PCL crosslinked network architecture with shape memory properties. POSS/PCL nanocomposites with molecular weight of 2,600 g/mol exhibiting shape memory behavior were synthesized and variation of crosslinker molar ratio was used to obtain POSS/PCL networks with different crosslink density (Alvarado-Tenorio et al., Macromolecules, 44, 5682, 2011). In that study it was shown that there are POSS crystals embedded in an amorphous PCL matrix, and the POSS crystals were ordered in a cubic nanostructure. In this work, it will be shown that elongation at room temperature of all the networks yielded a double-induced orientation (90º and 180º) of the POSS crystals, as indicated by the 101 reflection. Moreover, it was also detected stretched-induced crystallization of the otherwise amorphous PCL chains. Furthermore, SAXS data showed long periods in the meridional and equatorial orientations of 630 Å, 90 Å and 45 Å corresponding to a lamellar nanostructure of PCL chains. The induced bimodal orientation of the POSS-PCL molecular network will be correlated with its shape memory properties.

Use of Decomposition of Non-Thermoelastic Martensite for Structural Changes of CuZnAl Shape Memory Alloys

2014 ◽  
Vol 782 ◽  
pp. 427-430 ◽  
Author(s):  
Marek Vojtko ◽  
Pavol Zubko ◽  
Martin Ďurišin
Keyword(s):  
Mechanical Properties ◽  
Shape Memory ◽  
Structural Changes ◽  
Elevated Temperatures ◽  
Alpha Phase ◽  
Phase Region ◽  
Dual Phase ◽  
Temperature Decrease ◽  
Quenching Temperature ◽  
Shape Memory Properties

Cu22Zn4.6Al shape memory alloy shows memory phenomenon after quenching from dual phase region. Amount of shape memory effect continuously decreases with raised quenching temperature. Decrease is caused by increasing of amount of non-thermoelastic martensite in structure [. Approximately above 700°C there is no effect and martensite is non-thermoleastic. Non-thermoelastic martesite decomposes to alpha and gamma/beta phases at heating at elevated temperatures.[ This effect can be used for modification of structure and thus mechanical and shape memory properties. Some various types of structures were obtained and mechanical and shape memory properties were evaluated. Using of decomposition of non-thermoelastic martensite allows to obtain fine structure with the same amount of alpha phase and martensite as in basic state. This type of structure has better shape memory properties and higher mechanical properties.

A novel 3D-printable hydrogel with high mechanical strength and shape memory properties

2019 ◽  
Vol 7 (47) ◽  
pp. 14913-14922 ◽  
Author(s):  
Qiang Zhou ◽  
Kaixiang Yang ◽  
Jiaqing He ◽  
Haiyang Yang ◽  
Xingyuan Zhang
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Mechanical Strength ◽  
Shape Memory ◽  
Three Dimensional ◽  
High Mechanical Strength ◽  
Shape Memory Properties ◽  
Potential Applications

The three-dimensional (3D)-printing of hydrogels with excellent mechanical properties has attracted extensive attention owing to their potential applications in many fields.

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