Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
6.6
5.0
Journals
Polymers
Special Issues
Design and Manufacturing of Shape Memory Polymers and Active Structures
share announcement

Design and Manufacturing of Shape Memory Polymers and Active Structures

A special issue of Polymers (ISSN 2073-4360). This special issue belongs to the section "Polymer Chemistry".

Deadline for manuscript submissions: closed (31 December 2019) | Viewed by 23697

Special Issue Editor

Prof. Dr. Qi Ge

E-Mail Website
Guest Editor
Department of Mechanical and Energy Engineering, Southern University of Science and Technology, 1088 Xueyuan Avenue, Shenzhen 518055, China
Interests: 4D printing; smart materials and structures; 3D printing; mechanics of soft materials; soft robotics; flexible electronics
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Shape-memory polymers (SMPs) are polymeric smart materials which have the ability to return from a fixed temporary shape to their original permanent shape upon induction by an external stimulus such as heat, light, electric or magnetic field, or solution. Because of the capability of performing active actuation, SMPs have found various applications in aerospace, soft robots, biomedicals, and many other fields. In recent years, researchers have started to employ 3D printing to manufacture active structures made of SMPs. This emerging technology is now widely known as “4D Printing”. The design approaches that integrate nonlinear, multi-physics SMP models into complex multi-material 3D structures play key roles to guide the design and manufacturing of active structures with SMPs.

This Special Issue of Polymers will cover a broad range of research activities on the design and manufacturing of shape-memory polymers and active structures, including synthesis and characterization of SMPs, constitutive modelling of SMPs, design and manufacturing of active structures, and 4D printing with SMPs. In addition, review papers featuring progresses in a particular area are welcomed. This Special Issue aims to collect recent findings and comprehensive reviews from experts in this very active field of research and will hopefully be a useful source of information for researchers.

Prof. Qi Ge
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Polymers is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • shape-memory polymers
  • active structures
  • 4D printing
  • constitutive modeling
  • structure design and manufacturing

Published Papers (6 papers)

Download All Papers
Order results
Result details
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:

Research

12 pages, 3043 KiB  
Article
A Unidirectional Soft Dielectric Elastomer Actuator Enabled by Built-In Honeycomb Metastructures
by Kun Liu, Shitong Chen, Feifei Chen and Xiangyang Zhu
Polymers 2020, 12(3), 619; https://doi.org/10.3390/polym12030619 - 9 Mar 2020
Cited by 19 | Viewed by 4816
Abstract
Dielectric elastomer actuators (DEAs) are able to undergo large deformation in response to external electric stimuli and have been widely used to drive soft robotic systems, due to their advantageous attributes comparable to biological muscles. However, due to their isotropic material properties, it [...] Read more.
Dielectric elastomer actuators (DEAs) are able to undergo large deformation in response to external electric stimuli and have been widely used to drive soft robotic systems, due to their advantageous attributes comparable to biological muscles. However, due to their isotropic material properties, it has been challenging to generate programmable actuation, e.g., along a predefined direction. In this paper, we provide an innovative solution to this problem by harnessing honeycomb metastructures to program the mechanical behavior of dielectric elastomers. The honeycomb metastructures not only provide mechanical prestretches for DEAs but, more importantly, transfer the areal expansion of DEAs into directional deformation, by virtue of the inherent anisotropy. To achieve uniaxial actuation and maximize its magnitude, we develop a finite element analysis model and study how the prestretch ratios and the honeycomb structuring tailor the voltage-induced deformation. We also provide an easy-to-implement and scalable fabrication solution by directly printing honeycomb lattices made of thermoplastic polyurethane on dielectric membranes with natural bonding. The preliminary experiments demonstrate that our designed DEA is able to undergo unidirectional motion, with the nominal strain reaching up to 15.8%. Our work represents an initial step to program deformation of DEAs with metastructures. Full article
(This article belongs to the Special Issue Design and Manufacturing of Shape Memory Polymers and Active Structures)
►▼ Show Figures

Figure 1

14 pages, 5253 KiB  
Article
Electro-active Variable-Stiffness Corrugated Structure Based on Shape-Memory Polymer Composite
by Xiaobo Gong, Fang Xie, Liwu Liu, Yanju Liu and Jinsong Leng
Polymers 2020, 12(2), 387; https://doi.org/10.3390/polym12020387 - 8 Feb 2020
Cited by 21 | Viewed by 3529
Abstract
Shape-memory polymers (SMPs) can adjust their stiffness, lock a temporary shape, and recover the permanent shape upon an appropriate stimulus. They are applied in the field of morphing skins. This work presents a variable-stiffness corrugated sheet based on a carbon fiber felt (CFF)-reinforced [...] Read more.
Shape-memory polymers (SMPs) can adjust their stiffness, lock a temporary shape, and recover the permanent shape upon an appropriate stimulus. They are applied in the field of morphing skins. This work presents a variable-stiffness corrugated sheet based on a carbon fiber felt (CFF)-reinforced epoxy-based SMP composite that shows variable stiffness and extreme mechanical anisotropy for potential morphing skin applications. The corrugated sheet exhibits a variable stiffness with a change in temperature, which can help the skin adjust its stiffness according to different service environments. The corrugated sheet can be electrically heated rapidly and homogeneously due to its high electrical conductivity and enhanced heat transfer efficiency. Its Joule-heating effect acts as an effective active stimulation of the variable stiffness and shape-memory effect. The CFF-reinforced epoxy-based SMP composite was manufactured into a corrugated shape to obtain extreme mechanical anisotropy. The corrugated sheet shows a low in-plane stiffness to minimize the actuation energy, while it also possesses high out-of-plane stiffness to transfer the aerodynamic pressure load. Its mechanical properties, electrical heating performance, and shape-memory effect were investigated using experiments. The results show that the proposed SMP composite exhibits extreme mechanical anisotropy, considerable deformation ability, and variable stiffness induced by Joule heating without an external heater. Full article
(This article belongs to the Special Issue Design and Manufacturing of Shape Memory Polymers and Active Structures)
►▼ Show Figures

Graphical abstract

11 pages, 9125 KiB  
Communication
Shape-Memory-Recovery Characteristics of Microcellular Foamed Thermoplastic Polyurethane
by Chang-Seok Yun, Joo Seong Sohn and Sung Woon Cha
Polymers 2020, 12(2), 351; https://doi.org/10.3390/polym12020351 - 6 Feb 2020
Cited by 5 | Viewed by 2740
Abstract
We investigated the shape-recovery characteristics of thermoplastic polyurethane (TPU) with a microcellular foaming process (MCP). Additionally, we investigated the correlation between changes in the microstructure and the shape-recovery characteristics of the polymers. TPU was selected as the base material, and the shape-recovery characteristics [...] Read more.
We investigated the shape-recovery characteristics of thermoplastic polyurethane (TPU) with a microcellular foaming process (MCP). Additionally, we investigated the correlation between changes in the microstructure and the shape-recovery characteristics of the polymers. TPU was selected as the base material, and the shape-recovery characteristics were confirmed using a universal testing machine, by manufacturing dog-bone-type injection-molded specimens. TPUs are reticular polymers with both soft and hard segments. In this study, we investigated the shape-memory mechanism of foamed polymers by maximizing the shape-memory properties of these polymers through a physical foaming process. Toward this end, TPU specimens were prepared by varying the gas pressure, foaming temperature, and type of foaming gas in the batch MCP. The effects of internal structural changes were investigated. These experimental variables affected the microstructure and shape-recovery characteristics of the foamed polymer. The generated cell density changed, which affected the shape-recovery characteristics. In general, a higher cell density corresponded to a higher shape-recovery ratio. Full article
(This article belongs to the Special Issue Design and Manufacturing of Shape Memory Polymers and Active Structures)
►▼ Show Figures

Figure 1

14 pages, 3827 KiB  
Article
Hybrid Nanocomposites of Cellulose/Carbon-Nanotubes/Polyurethane with Rapidly Water Sensitive Shape Memory Effect and Strain Sensing Performance
by Guanzheng Wu, Yanjia Gu, Xiuliang Hou, Ruiqing Li, Huizhen Ke and Xueliang Xiao
Polymers 2019, 11(10), 1586; https://doi.org/10.3390/polym11101586 - 27 Sep 2019
Cited by 45 | Viewed by 4556
Abstract
In this work, a fast water-responsive shape memory hybrid polymer based on thermoplastic polyurethane (TPU) was prepared by crosslinking with hydroxyethyl cotton cellulose nanofibers (CNF-C) and multi-walled carbon nanotubes (CNTs). The effect of CNTs content on the electrical conductivity of TPU/CNF-C/CNTs nanocomposite was [...] Read more.
In this work, a fast water-responsive shape memory hybrid polymer based on thermoplastic polyurethane (TPU) was prepared by crosslinking with hydroxyethyl cotton cellulose nanofibers (CNF-C) and multi-walled carbon nanotubes (CNTs). The effect of CNTs content on the electrical conductivity of TPU/CNF-C/CNTs nanocomposite was investigated for the feasibility of being a strain sensor. In order to know its durability, the mechanical and water-responsive shape memory effects were studied comprehensively. The results indicated good mechanical properties and sensing performance for the TPU matrix fully crosslinked with CNF-C and CNTs. The water-induced shape fixity ratio (Rf) and shape recovery ratio (Rr) were 49.65% and 76.64%, respectively, indicating that the deformed composite was able to recover its original shape under a stimulus. The TPU/CNF-C/CNTs samples under their fixed and recovered shapes were tested to investigate their sensing properties, such as periodicity, frequency, and repeatability of the sensor spline under different loadings. Results indicated that the hybrid composite can sense large strains accurately for more than 103 times and water-induced shape recovery can to some extent maintain the sensing accuracy after material fatigue. With such good properties, we envisage that this kind of composite may play a significant role in developing new generations of water-responsive sensors or actuators. Full article
(This article belongs to the Special Issue Design and Manufacturing of Shape Memory Polymers and Active Structures)
►▼ Show Figures

Figure 1

14 pages, 3651 KiB  
Article
Shape Memory Polyurethane with Porous Architectures for Potential Applications in Intracranial Aneurysm Treatment
by Jingyu Wang, Robert Kunkel, Jishan Luo, Yuhua Li, Hong Liu, Bradley N. Bohnstedt, Yingtao Liu and Chung-Hao Lee
Polymers 2019, 11(4), 631; https://doi.org/10.3390/polym11040631 - 5 Apr 2019
Cited by 18 | Viewed by 4475
Abstract
Conventional endovascular embolization of intracranial (or brain) aneurysms using helical detachable platinum coils can be time-consuming and occasionally requires retreatment due to incomplete coil packing. These shortcomings create a need for new biomedical devices and methods of achieving brain aneurysm occlusion. This paper [...] Read more.
Conventional endovascular embolization of intracranial (or brain) aneurysms using helical detachable platinum coils can be time-consuming and occasionally requires retreatment due to incomplete coil packing. These shortcomings create a need for new biomedical devices and methods of achieving brain aneurysm occlusion. This paper presents a biocompatible and highly porous shape memory polymer (SMP) material with potential applications in the development of novel endovascular devices for treating complex intracranial aneurysms. The novel highly porous polyurethane SMP is synthesized as an open cell foam material with a glass transition temperature (Tg) of 39 °C using a sugar particle leaching method. Once heated above the Tg, the compressed SMP foam is able to quickly return to its original shape. An electrical resistance heating method is also employed to demonstrate a potential triggering design for the shape recovery process in future medical applications. The mechanical properties of the developed SMP foam are characterized at temperatures up to 10 °C above the respective Tg. The results from this work demonstrate that the porous SMP material developed in this study and the electrical resistance heating trigger mechanism provide a solid foundation for future design of biomedical devices to enhance the long-term therapeutic outcomes of endovascular intracranial aneurysm treatments. Full article
(This article belongs to the Special Issue Design and Manufacturing of Shape Memory Polymers and Active Structures)
►▼ Show Figures

Graphical abstract

15 pages, 4501 KiB  
Article
Analysis of the Process Parameters for Obtaining a Stable Electrospun Process in Different Composition Epoxy/Poly ε-Caprolactone Blends with Shape Memory Properties
by Alvaro Iregui, Lourdes Irusta, Loli Martin and Alba González
Polymers 2019, 11(3), 475; https://doi.org/10.3390/polym11030475 - 12 Mar 2019
Cited by 15 | Viewed by 2900
Abstract
In this work Poly ε-caprolactone (PCL)/ Diglycidyl ether of bisphenol A (DGEBA) blends were electrospun and the obtained mats were UV cured to achieve shape memory properties. In the majority of studies, when blends with different compositions are electrospun, the process variables such [...] Read more.
In this work Poly ε-caprolactone (PCL)/ Diglycidyl ether of bisphenol A (DGEBA) blends were electrospun and the obtained mats were UV cured to achieve shape memory properties. In the majority of studies, when blends with different compositions are electrospun, the process variables such as voltage or flow rate are fixed independently of the composition and consequently the quality of the fibers is not optimized in all of the range studied. In the present work, using the design of experiments methodology, flow rate and voltage required to obtain a stable process were evaluated as responses in addition to the fiber diameter and shape memory properties. The results showed that the solution concentration and amount of PCL played an important role in the voltage and flow rate. For the shape memory properties excellent values were achieved and no composition dependence was observed. In the case of fiber diameter, similar results to previous works were observed. Full article
(This article belongs to the Special Issue Design and Manufacturing of Shape Memory Polymers and Active Structures)
►▼ Show Figures

Graphical abstract

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-6
Back to TopTop