Programming 2D sheets to form 3D shapes is significant for flexible electronics, soft robots, and biomedical devices. Stress regulation is one of the most used methods, during which external force is ...usually needed to keep the stress, leading to complex processing setups. Here, by introducing dynamic diselenide bonds into shape‐memory materials, unconstrained shape programming with light is achieved. The material could hold and release internal stress by themselves through the shape‐memory effect, simplifying programming setups. The fixed stress could be relaxed by light to form stress gradients, leading to out‐of‐plane deformations through asymmetric contractions. Benefiting from the variability of light irradiation, complex 3D configurations can be obtained conveniently from 2D polymer sheets. Besides, remotely controlled “4D assembly” and actuation, including object transportation and self‐lifting, can be achieved by sequential deformation. Taking advantage of the high spatial resolution of light, this material can also produce 3D microscopic patterns. The light‐induced stress gradients significantly simplify 3D shape programming procedures with improved resolution and complexity and have great potential in soft robots, smart actuators, and anti‐counterfeiting techniques.
Through introducing light‐responsive diselenide bonds into polymer films, homogeneous stress fixed by shape‐memory effect can be relaxed to form a stress gradient. Once the stress gradient is activated, various deformations, including bending, folding, twisting, and helix, can be realized through the asymmetric contraction, which can be further combined for 3D shape programming, sequential deformation, and microscopic optical patterning.
Herein, a novel microfibrillated cellulose (MFC) reinforced natural polymer-based sponge composed of carboxymethyl chitosan (CMC) and oxidized starch (OS) with hemostatic, repairing-promoting, and ...antimicrobial performances was fabricated for chronic wound repair. When the content of MFC reached 1.2 wt%, the prepared sponge exhibited ultra-fast water or blood-trigged shape recovery property within 3 s. Moreover, sponge was functionally modified with silver nanoparticles (AgNPs) and recombinant humanized collagen type III (rhCol III). The AgNPs and rhCol III loaded sponge (A-Ag/III) could effectively kill a broad spectrum of pathogenic microbes, promote the proliferation and migration of L929 cells in vitro. Due to their erythrocyte-aggregating ability and positive-charge feature of CMC, the A-Ag/III displayed rapid hemostasis ability. Furthermore, the in vivo animal experiment demonstrated the A-Ag/III could promote wound repair by inhibiting inflammation, promoting angiogenesis, and cell proliferation.
•A novel hemostatic MFC reinforced multifunctional sponge was developed.•The prepared sponges displayed superfast water/blood-trigged shape recovery property.•The prepared sponges showed a promoting effect on diabetic wound healing.
3D and 4D printing: From innovation to evolution Mallakpour, Shadpour; Tabesh, Farbod; Hussain, Chaudhery Mustansar
Advances in colloid and interface science,
August 2021, 2021-08-00, 20210801, Volume:
294
Journal Article
Peer reviewed
The world and science are moving forward nonstop. Every day, we see novel technologies that are coming to improve life quality. One of them is 3D printing or additive manufacturing. This technology ...covers the shortage of the current manufacturing technologies, and it has been enhanced by introducing smart materials like smart polymers as feed. The following product can adapt to circumstance conditions such as temperature changes, compression alteration, etc. These responses resulted in an advanced 3D printing technology called 4D printing. 3D and 4D printing technologies found their applications in all areas and industry sizes, from home-scale to large-scale industries. Regardless of all advantages of these technologies, there are still some shortages like low printing speed. But this never stops their progression and promotion. In this review, we aimed to cover general knowledge about 3D and 4D printing and their recent applications in various fields.
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•3D and 4D printing are new technologies that opening new windows to the future.•4D printing is actually combination of 3D printing and time.•3D and 4D printing are successful in producing difficult shapes.•3D and 4D printing are applicable from small to large-scale industries.
The rapid development of additive manufacturing and advances in shape memory materials have fueled the progress of four-dimensional （4D） printing. With the right external stimulus, the need for human ...interaction, sensors, and batteries will be eliminated, and by using additive manufacturing, more complex devices and parts can be produced. With the current understanding of shape memory mechanisms and with improved design for additive manufacturing, reversibility in 4D printing has recently been proven to be feasible. Conventional one-way 4D printing requires human interaction in the programming （or shapesetting） phase, but reversible 4D printing, or two-way 4D printing, will fully eliminate the need for human interference, as the programming stage is replaced with another stimulus. This allows reversible 4D printed parts to be fully dependent on external stimuli; parts can also be potentially reused after every recovery, or even used in continuous cycles-an aspect that carries industrial appeal. This paper presents a review on the mechanisms of shape memory materials that have led to 4D printing, current findings regarding 4D printing in alloys and polymers, and their respective limitations. The reversibility of shape memory materials and their feasibility to be fabricated using three-dimensional （3D） printing are summarized and critically analyzed. For reversible 4D printing, the methods of 3D printing, mechanisms used for actuation, and strategies to achieve reversibility are also highlighted. Finally, prospective future research directions in reversible 4D printing are suggested.
In this study, a coaxial additive manufacturing process was developed for four-dimensional (4D) printing with continuous carbon fiber-reinforced shape memory polymers (SMPs). These materials have ...potential applications in the aerospace, automotive, and biomedical industries due to their high strength-to-weight ratio and shape memory properties. The mechanical and thermal properties of the SMPs were evaluated and the effects of printing parameters on printability and carbon fiber volume fraction were analyzed to determine optimal printing conditions. It was found that even a small amount of carbon fiber significantly improved the mechanical properties of the 4D printed samples. The shape memory properties of the printed samples were also examined, and it was found that the structure was able to recover the original shape quickly at low-temperature programming, making it suitable for load-bearing structures. At high-temperature programming, the structure retained the programmed shape well, but recovery of the original shape was slower and incomplete. The use of continuous carbon fiber reinforced SMPs also allows for Joule heating to be used for shape recovery, with the applied voltage able to control the shape recovery process. A high level of deformation recovery (95%) was also achieved in highly deformed structures.
Multimodal self‐sustainable autonomous locomotions integrated into one individual system, are high‐level intelligent behavioral characteristics of living organisms and are the scientific hotspot of ...bionic soft actuators. Here, we report a light‐fueled soft actuator with multimodal self‐sustainable movements based on a Seifert ribbon bounded by a Hopf link. The Seifert ribbon actuator can self‐sense the illumination area adjustment, and the actuation component becomes either a discontinuous strip‐like structure or a continuous toroidal structure, which can realize adaptive switches between self‐sustained oscillatory and rotary motions. The two motion modes are applied to the self‐oscillatory piezoelectric generation and self‐rotational work multiplication of cargo transport, respectively. The unique smartness of Seifert surface topology advances the level of actuation intelligence with broad implications for the adaptability, multifunctionality, and autonomy of soft robots.
A light‐driven liquid crystal elastomer ribbon actuator with multimodal self‐sustainable autonomous locomotion is constructed based on the topology of Seifert surface. The Seifert ribbon actuator can self‐sense the illumination area adjustment, and realize the adaptive switches between self‐sustained oscillatory and rotary motions.
The purpose of 4D printing is to embed a product design into a deformable smart material using a traditional 3D printer. The 3D printed object can be assembled or transformed into intended designs by ...applying certain conditions or forms of stimulation such as temperature, pressure, humidity, pH, wind, or light. Simply put, 4D printing is a continuum of 3D printing technology that is now able to print objects which change over time. In previous studies, many smart materials were shown to have 4D printing characteristics. In this paper, we specifically review the current application, respective activation methods, characteristics, and future prospects of various polymeric materials in 4D printing, which are expected to contribute to the development of 4D printing polymeric materials and technology.
Eucommia ulmoides rubber (EUR) is a high-molecular polymer of trans-1,4-polyisoprene, conventionally synthesized by a sequential condensation of isopentenyl diphosphates to its isomer of ...dimethylallyl diphosphate in trans configuration. The extraction methods for EUR generally include mechanical method, alkali extraction, solvent extraction, and microbial method. Compared with others, microbial method can obtain higher purity EUR and retain its original appearance furthest with less environmental pollution as well as less production cost, implying that it might become the primary extraction technology. EUR has dual characteristics of rubber and plastic. The utilization of EUR is highly dependent on the crystallinity and crosslinking degree which can be modified by physical or chemical methods, to help producing the EUR industrial products that can have multi-functionalities. The objective of this review is to investigate the recent insights of the biosynthesis, extraction, the structure and properties, the modification as well as application of EUR to promote the research and utilization of EUR, to meet the requirements of various engineering applications. EUR is expected to partially substitute natural rubber with broad prospects for development and utilization.
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•Eucommia ulmoides rubber (EUR) is high molecular polymer of trans-1,4-Polyisoprene.•Various physicochemical methods for EUR extraction are reviewed in this work.•EUR possess the dual characteristics of rubber and plastic.•Industrial application of EUR is highly dependent on the crystallinity and crosslinking degree.•Various EUR based engineering materials are clarified.
Shaping tissue with shape memory materials Huang, W.M.; Song, C.L.; Fu, Y.Q. ...
Advanced drug delivery reviews,
April 2013, 2013-Apr, 2013-04-00, 20130401, Volume:
65, Issue:
4
Journal Article
Peer reviewed
After being severely and quasi-plastically deformed, shape memory materials are able to return to their original shape at the presence of the right stimulus. After a brief presentation about the ...fundamentals, including various shape memory effects, working mechanisms, and typical shape memory materials for biomedical applications, we summarize some major applications in shaping tissue with shape memory materials. The focus is on some most recent development. Outlook is also discussed at the end of this paper.
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