Frontally polymerizable shape memory polymer for 3D printing of free-standing structures

2021 ◽  
Author(s):  
Yongsan An ◽  
Joon Hyeok Jang ◽  
Ji Ho Youk ◽  
Woong-Ryeol Yu
Keyword(s):  
Shape Memory ◽  
Memory Performance ◽  
Shape Memory Polymer ◽  
Three Dimensional ◽  
Frontal Polymerization ◽  
4D Printing ◽  
Free Standing ◽  
Time Shape ◽  
Standing Structure ◽  
3D Printed

Abstract Four-dimensional (4D) printing is used to describe three-dimensional (3D)-printed objects with properties that change over time. Shape memory polymers (SMPs) are representative materials for 4D printing technologies. The ability to print geometrically complex, free-standing forms with SMPs is crucial for successful 4D printing. In this study, an SMP capable of frontal polymerization featuring exothermic self-propagation was synthesized by adding cyclooctene to a poly(dicyclopentadiene) network, resulting in switching segments. The rheological properties of this SMP were controlled by adjusting incubation time. A nozzle system was designed such that the SMP could be printed with simultaneous polymerization to yield a free-standing structure. The printing speed was set to 3 cm/min according to the frontal polymerization speed. A free-standing, hexagonal spiral was successfully printed and printed spiral structure showed excellent shape memory performance with a fixity ratio of about 98% and a recovery ratio of 100%, thereby demonstrating the 3D printability and shape memory performance of frontally polymerizable SMPs.

4D Printing of Complex Ceramic Structures via Controlling Zirconia Contents and Patterns

2021 ◽  
Author(s):  
Zhicheng Rong ◽  
Chang Liu ◽  
Yingbin Hu
Keyword(s):  
3D Printing ◽  
Shape Memory ◽  
Shape Change ◽  
Three Dimensional ◽  
Ceramic Materials ◽  
Full Potential ◽  
Sintering Process ◽  
4D Printing ◽  
3D Printed ◽  
Dynamic Components

Abstract In recent years, more and more attentions have been attracted on integrating three-dimensional (3D) printing with fields (such as magnetic field) or innovating new methods to reap the full potential of 3D printing in manufacturing high-quality parts and processing nano-scaled composites. Among all of newly innovated methods, four-dimensional (4D) printing has been proved to be an effective way of creating dynamic components from simple structures. Common feeding materials in 4D printing include shape memory hydrogels, shape memory polymers, and shape memory alloys. However, few attempts have been made on 4D printing of ceramic materials to shape ceramics into intricate structures, owing to ceramics’ inherent brittleness nature. Facing this problem, this investigation aims at filling the gap between 4D printing and fabrication of complex ceramic structures. Inspired by swelling-and-shrinking-induced self-folding, a 4D printing method is innovated to add an additional shape change of ceramic structures by controlling ZrO2 contents and patterns. Experimental results evidenced that by deliberately controlling ZrO2 contents and patterns, 3D-printed ceramic parts would undergo bending and twisting during the sintering process. To demonstrate the capabilities of this method, more complex structures (such as a flower-like structure) were fabricated. In addition, functional parts with magnetic behaviors were 4D-printed by incorporating iron into the PDMS-ZrO2 ink.

scholarly journals 3D Printed Shape Memory Polymers Produced via Direct Pellet Extrusion

Micromachines ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 87
Author(s):  
Trenton Cersoli ◽  
Alexis Cresanto ◽  
Callan Herberger ◽  
Eric MacDonald ◽  
Pedro Cortes
Keyword(s):  
3D Printing ◽  
Shape Memory ◽  
Memory Performance ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Qr Code ◽  
Thermal Stimulus ◽  
Conventional Film ◽  
3D Printed ◽  
Smart Actuator

Shape memory polymers (SMPs) are materials capable of changing their structural configuration from a fixed shape to a temporary shape, and vice versa when subjected to a thermal stimulus. The present work has investigated the 3D printing process of a shape memory polymer (SMP)-based polyurethane using a material extrusion technology. Here, SMP pellets were fed into a printing unit, and actuating coupons were manufactured. In contrast to the conventional film-casting manufacturing processes of SMPs, the use of 3D printing allows the production of complex parts for smart electronics and morphing structures. In the present work, the memory performance of the actuating structure was investigated, and their fundamental recovery and mechanical properties were characterized. The preliminary results show that the assembled structures were able to recover their original conformation following a thermal input. The printed parts were also stamped with a QR code on the surface to include an unclonable pattern for addressing counterfeit features. The stamped coupons were subjected to a deformation-recovery shape process, and it was observed that the QR code was recognized after the parts returned to their original shape. The combination of shape memory effect with authentication features allows for a new dimension of counterfeit thwarting. The 3D-printed SMP parts in this work were also combined with shape memory alloys to create a smart actuator to act as a two-way switch to control data collection of a microcontroller.

scholarly journals Lightweight Microlattice With Tunable Mechanical Properties Using 3D Printed Shape Memory Polymer

2018 ◽  
Author(s):  
Chen Yang ◽  
Manish Boorugu ◽  
Andrew Dopp ◽  
Howon Lee
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Shape Memory ◽  
Shape Memory Polymer ◽  
Three Dimensional ◽  
Temperature Shift ◽  
Spatial Arrangement ◽  
Mechanical Metamaterials ◽  
3D Printed ◽  
Varying Environments

Metamaterials are architected artificial materials engineered to exhibit properties not typically found in natural materials. Increasing attention has recently been given to mechanical metamaterials with unprecedented mechanical properties including high stiffness, strength, or/and resilience even at extremely low density. These unusual mechanical performances emerge from the three-dimensional (3D) spatial arrangement of the micro-structural elements designed to effectively distribute mechanical loads. Recent advances in additive manufacturing in micro-/nano-scale have catalyzed the growing interest in this field. This work presents a new lightweight microlattice with tunable and recoverable mechanical properties using a three-dimensionally architected shape memory polymer (SMP). SMP microlattices were fabricated utilizing our micro additive manufacturing technique called projection micro-stereolithography (PμSL), which uses a digital micro-mirror device (DMD™) as a dynamically reconfigurable photomask. We use a photo-crosslinkable and temperature-responsive SMP which can retain its large deformation until heated for spontaneous shape recovery. In addition, it exhibits remarkable elastic modulus changes during this transition. We demonstrate that mechanical responses of the micro 3D printed SMP microlattice can be reversibly tuned by temperature control. Mechanical testing result showed that stiffness of a SMP microlattice changed by two orders of magnitude by a moderate temperature shift by 60°C. Furthermore, the shape memory effect of the SMP allows for full restitution of the original shape of the microlattice upon heating even after substantial mechanical deformation. Mechanical metamaterials with lightweight, reversibly tunable properties, and shape recoverability can potentially lead to new smart structural systems that can effectively react and adapt to varying environments or unpredicted loads.

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 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.

3D printed self-expandable vascular stents from biodegradable shape memory polymer

2018 ◽  
Vol 37 (8) ◽  
pp. 3222-3228 ◽  
Author(s):  
Han Jia ◽  
Shu-Ying Gu ◽  
Kun Chang
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Vascular Stents ◽  
3D Printed

3D printed biodegradable functional temperature-stimuli shape memory polymer for customized scaffoldings

2020 ◽  
Vol 108 ◽  
pp. 103781 ◽  
Author(s):  
Akash Pandey ◽  
Gurminder Singh ◽  
Sunpreet Singh ◽  
Kanishak Jha ◽  
Chander Prakash
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
3D Printed

scholarly journals Control-Based 4D Printing: Adaptive 4D-Printed Systems

2020 ◽  
Vol 10 (9) ◽  
pp. 3020 ◽  
Author(s):  
Ali Zolfagharian ◽  
Akif Kaynak ◽  
Mahdi Bodaghi ◽  
Abbas Z. Kouzani ◽  
Saleh Gharaie ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Advanced Manufacturing ◽  
Wearable Electronics ◽  
Stimuli Responsive ◽  
4D Printing ◽  
Control Units ◽  
Printed Sensors ◽  
3D Printed ◽  
Dynamic Structures ◽  
And Control

Building on the recent progress of four-dimensional (4D) printing to produce dynamic structures, this study aimed to bring this technology to the next level by introducing control-based 4D printing to develop adaptive 4D-printed systems with highly versatile multi-disciplinary applications, including medicine, in the form of assisted soft robots, smart textiles as wearable electronics and other industries such as agriculture and microfluidics. This study introduced and analysed adaptive 4D-printed systems with an advanced manufacturing approach for developing stimuli-responsive constructs that organically adapted to environmental dynamic situations and uncertainties as nature does. The adaptive 4D-printed systems incorporated synergic integration of three-dimensional (3D)-printed sensors into 4D-printing and control units, which could be assembled and programmed to transform their shapes based on the assigned tasks and environmental stimuli. This paper demonstrates the adaptivity of these systems via a combination of proprioceptive sensory feedback, modeling and controllers, as well as the challenges and future opportunities they present.

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