Autonomous Off‐Equilibrium Morphing Pathways of a Supramolecular Shape‐Memory Polymer

2021 ◽  
pp. 2102473
Author(s):  
Wenjun Peng ◽  
Guogao Zhang ◽  
Qian Zhao ◽  
Tao Xie
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer

scholarly journals Design of Shape Memory Thermoplastic Material Systems for FDM-Type Additive Manufacturing

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4254
Author(s):  
Paulina A. Quiñonez ◽  
Leticia Ugarte-Sanchez ◽  
Diego Bermudez ◽  
Paulina Chinolla ◽  
Rhyan Dueck ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Shape Memory ◽  
Thermomechanical Processing ◽  
Material Selection ◽  
Shape Memory Polymer ◽  
Fused Filament Fabrication ◽  
Materials Development ◽  
Thermoplastic Material ◽  
Polymer Systems ◽  
Injection Molded

The work presented here describes a paradigm for the design of materials for additive manufacturing platforms based on taking advantage of unique physical properties imparted upon the material by the fabrication process. We sought to further investigate past work with binary shape memory polymer blends, which indicated that phase texturization caused by the fused filament fabrication (FFF) process enhanced shape memory properties. In this work, two multi-constituent shape memory polymer systems were developed where the miscibility parameter was the guide in material selection. A comparison with injection molded specimens was also carried out to further investigate the ability of the FFF process to enable enhanced shape memory characteristics as compared to other manufacturing methods. It was found that blend combinations with more closely matching miscibility parameters were more apt at yielding reliable shape memory polymer systems. However, when miscibility parameters differed, a pathway towards the creation of shape memory polymer systems capable of maintaining more than one temporary shape at a time was potentially realized. Additional aspects related to impact modifying of rigid thermoplastics as well as thermomechanical processing on induced crystallinity are also explored. Overall, this work serves as another example in the advancement of additive manufacturing via materials development.

scholarly journals Pressure Orientation-Dependent Recovery of 3D-Printed PLA Objects with Varying Infill Degree

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1275 ◽  
Author(s):  
Guido Ehrmann ◽  
Andrea Ehrmann
Keyword(s):  
Shape Memory ◽  
Fused Deposition Modeling ◽  
Static Load ◽  
Shape Memory Polymer ◽  
Applied Pressure ◽  
Poly Lactic Acid ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
Load Tests ◽  
3D Printed

Poly(lactic acid) is not only one of the most often used materials for 3D printing via fused deposition modeling (FDM), but also a shape-memory polymer. This means that objects printed from PLA can, to a certain extent, be deformed and regenerate their original shape automatically when they are heated to a moderate temperature of about 60–100 °C. It is important to note that pure PLA cannot restore broken bonds, so that it is necessary to find structures which can take up large forces by deformation without full breaks. Here we report on the continuation of previous tests on 3D-printed cubes with different infill patterns and degrees, now investigating the influence of the orientation of the applied pressure on the recovery properties. We find that for the applied gyroid pattern, indentation on the front parallel to the layers gives the worst recovery due to nearly full layer separation, while indentation on the front perpendicular to the layers or diagonal gives significantly better results. Pressing from the top, either diagonal or parallel to an edge, interestingly leads to a different residual strain than pressing from front, with indentation on top always firstly leading to an expansion towards the indenter after the first few quasi-static load tests. To quantitatively evaluate these results, new measures are suggested which could be adopted by other groups working on shape-memory polymers.

scholarly journals Harnessing reversible dry adhesion using shape memory polymer microparticles

RSC Advances ◽  
2021 ◽  
Vol 11 (32) ◽  
pp. 19616-19622
Author(s):  
Wenbing Li ◽  
Junhao Liu ◽  
Wanting Wei ◽  
Kun Qian
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Memory Effects ◽  
Reversible Adhesion ◽  
Dry Adhesion ◽  
Bonding Property ◽  
Shape Memory Effects ◽  
Polymer Microparticles

Shape memory polymers can provide excellent bonding property because of their shape memory effects. This paper proposes an adhesive unit that is capable of repeatable smart adhesion and exhibits reversible adhesion under heating.

scholarly journals In Situ Generation of Green Hybrid Nanofibrillar Polymer-Polymer Composites—A Novel Approach to the Triple Shape Memory Polymer Formation

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1900
Author(s):  
Ramin Hosseinnezhad ◽  
Iurii Vozniak ◽  
Fahmi Zaïri
Keyword(s):  
Polymer Blends ◽  
Shape Memory ◽  
Shape Memory Polymer ◽  
Cellulose Nanofibers ◽  
Polymeric Materials ◽  
Novel Approach ◽  
Phase Transition Temperatures ◽  
Triple Shape Memory

The paper discusses the possibility of using in situ generated hybrid polymer-polymer nanocomposites as polymeric materials with triple shape memory, which, unlike conventional polymer blends with triple shape memory, are characterized by fully separated phase transition temperatures and strongest bonding between the polymer blends phase interfaces which are critical to the shape fixing and recovery. This was demonstrated using the three-component system polylactide/polybutylene adipateterephthalate/cellulose nanofibers (PLA/PBAT/CNFs). The role of in situ generated PBAT nanofibers and CNFs in the formation of efficient physical crosslinks at PLA-PBAT, PLA-CNF and PBAT-CNF interfaces and the effect of CNFs on the PBAT fibrillation and crystallization processes were elucidated. The in situ generated composites showed drastically higher values of strain recovery ratios, strain fixity ratios, faster recovery rate and better mechanical properties compared to the blend.

scholarly journals Clinical experience with a shape memory polymer peripheral vascular embolisation plug: a case series

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Robert A. Morgan ◽  
Ian Loftus ◽  
Lakshmi Ratnam ◽  
Raj Das ◽  
Leto Mailli ◽  
...  
Keyword(s):  
Shape Memory ◽  
Clinical Experience ◽  
Iliac Artery ◽  
Shape Memory Polymer ◽  
Endovascular Aneurysm Repair ◽  
Case Series ◽  
Artery Aneurysm ◽  
Gelatin Sponge ◽  
Peripheral Vasculature ◽  
Small Series

Abstract Background Shape memory polymers are materials that are manufactured in a certain shape, can be stored in a temporary deformed shape, and then return to – or remember – their original shape upon exposure to external stimuli such as temperature and moisture. This property lends itself to application in endovascular medical devices. Peripheral vasculature embolisation devices incorporating this novel technology have become commercially available and this case series, where the data were collected as part of a post market registry, outlines initial clinical experience with these novel devices. Results Eight cases are described in this series. The disease state/conditions for which embolisation was indicated were right common iliac artery aneurysms (n = 3), a type II endoleak into the thoracic aorta following thoracic endovascular aneurysm repair (n = 1), a left inferior gluteal artery aneurysm (n = 1), left internal iliac artery aneurysms (n = 2), and a case of splenomegaly, where splenectomy was planned after the embolisation procedure (n = 1). Target arteries were 5–10 mm in diameter. In each case, at least one IMPEDE Embolization Plug (IMP-Device) of an appropriate diameter was used. All procedures were technically successful and target vessel thrombosis was achieved in all cases. Follow-up imaging available during the 45–90-day data collection timeframe showed sustained vessel occlusion. This case series includes examples of situations commonly encountered when embolising the peripheral vasculature, namely, the use of one or multiple devices in a single vessel and in combination with the use of other embolic devices (e.g., microcoils, gelatin sponge, and PVA particles) in the same case. There were no adverse events related to the specific use of the device. Conclusions This small series illustrates the safety and efficacy of this novel sponge-based embolic device for the embolisation of small and medium sized arteries and further experience will demonstrate the utility of the shape memory polymer devices.

scholarly journals Structural multi-colour invisible inks with submicron 4D printing of shape memory polymers

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wang Zhang ◽  
Hao Wang ◽  
Hongtao Wang ◽  
John You En Chan ◽  
Hailong Liu ◽  
...  
Keyword(s):  
Shape Memory ◽  
Information Hiding ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Photonic Devices ◽  
Temperature Sensitive ◽  
4D Printing ◽  
Two Photon ◽  
Shape Memory Effects ◽  
Nanoscale Structure

AbstractFour-dimensional (4D) printing of shape memory polymer (SMP) imparts time responsive properties to 3D structures. Here, we explore 4D printing of a SMP in the submicron length scale, extending its applications to nanophononics. We report a new SMP photoresist based on Vero Clear achieving print features at a resolution of ~300 nm half pitch using two-photon polymerization lithography (TPL). Prints consisting of grids with size-tunable multi-colours enabled the study of shape memory effects to achieve large visual shifts through nanoscale structure deformation. As the nanostructures are flattened, the colours and printed information become invisible. Remarkably, the shape memory effect recovers the original surface morphology of the nanostructures along with its structural colour within seconds of heating above its glass transition temperature. The high-resolution printing and excellent reversibility in both microtopography and optical properties promises a platform for temperature-sensitive labels, information hiding for anti-counterfeiting, and tunable photonic devices.

Sign in / Sign up

Export Citation Format

Share Document