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Self-healing and recyclable polymer materials are being developed through extensive investigations on noncovalent bond interactions. However, they typically exhibit inferior mechanical properties. Therefore, the present study is aimed at synthesizing a polyurethane–urea elastomer with excellent mechanical properties and shape-memory-assisted self-healing behavior. In particular, the introduction of coordination and hydrogen bonds into elastomer leads to the optimal elastomer exhibiting good mechanical properties (strength, 76.37 MPa; elongation at break, 839.10%; toughness, 308.63 MJ m−3) owing to the phased energy dissipation mechanism involving various supramolecular interactions. The elastomer also demonstrates shape-memory properties, whereby the shape recovery force that brings damaged surfaces closer and facilitates self-healing. Surprisingly, all specimens exhibite clustering-triggered emission, with cyan fluorescence is observed under ultraviolet light. The strategy reported herein for developing multifunctional materials with good mechanical properties can be leveraged to yield stimulus-responsive polymers and smart seals. Polymers formed with non-covalent bonds are increasingly being developed, but often show inferior mechanical properties. Here, the authors report the development of high performances polyurethane-urea elastomer with shape-memory assisted self-healing behaviour [ABSTRACT FROM AUTHOR]

To meet a variety of application scenarios, high‐performance shape memory polymers require not only excellent mechanical and shape memory properties but also a multistimulus response. Herein, this article reports a near infrared (NIR) light‐triggered thermosetting shape memory polyimide (PI)/reduced graphene oxide (rGO) nanocomposite with a high transition temperature, excellent shape memory behaviors, superior robustness, and fast light‐induced shape recovery. The nanocomposite exhibits unexceptionable mechanical properties with breaking strain up to 44.1% and toughness up to 41.7 MJ m−3 at a low content of GO (1 wt%) on account of the good dispersion of GO in the PI matrix and the formed hierarchical structure similar to Nacre. The nanocomposites also have high glass transition temperatures above 200 °C and exhibit a great high‐temperature shape memory effect with a shape fixation rate above 99% and a shape recovery rate above 98%. In addition, with the aid of the efficient photothermal conversion property of rGO, enabling the induction of a temporary shape that completely recovers to the original shape within 7 s by sequential NIR irradiation. It is envisioned that high‐performance nanocomposites with high‐temperature shape memory and excellent mechanical and multistimuli properties will be widely applied in harsh environments, such as alarms, actuation, and so on. [ABSTRACT FROM AUTHOR]

The rapid development of 4D printing provides a potential strategy for the fabrication of deployable medical devices (DMD). The minimally invasive surgery to implant the DMD into the body is critical, 4D printing DMD allows the well‐defined device to be implanted with a high‐compacted shape and transformed into their designed shape to meet the requirement. Herein, a 4D printing tissue engineering material is developed with excellent biocompatibility and shape memory effect based on the photocrosslinked polycaprolactone (PCL). The fast thiol‐acrylate click reaction is applied for photocrosslinking of the acrylates capped star polymer (s‐PCL‐MA) with poly‐thiols, that enable the 3D printing for the DMD fabrication. The cell viability, erythrocyte hemolysis, and platelet adhesion results indicate the excellent biocompatibility of the 4D printing polymer, especially the biological subcutaneous implantation results confirm the promote tissue growth and good histocompatibility. A 4D printing stent with deformable shape and recovery at a temperature close to human body temperature demonstrated the potential application as DMD. In addition, the everolimus is loaded to the polymer (ps1‐PCL) through host‐guest coordination with β‐cyclodextrin as the core of the star polymer, which shows sustained drug release and improved body's inflammatory response. [ABSTRACT FROM AUTHOR]

Although polymer-based self-lubricating materials have rapidly developed recently, intelligent lubricating materials with self-adaptable lubrication with external conditions changing are highly demanded, especially for harsh conditions. Herein, a shape memory epoxy resin based on the biphenyl units (BPEP) with tunable tribological behavior was systematically studied. X-ray diffraction (XRD), field emission scanning electron microscope (SEM), laser confocal three-dimensional profiler, and optical microscope were applied to analyze the friction and wear mechanism. Due to the presence of the specific biphenyl structural units, which could be performed a switching phase between crystalline and amorphous, that allows the self-assembly of the polymer chain under π–π interaction. As a result, the improving mechanical properties enable the BPEP to perform outstanding self-lubricating in a wide temperature range, and the friction coefficient (COF) can be tuned in a wide range of 0.10~0.175 by adjusting the temperature. The shape memory effect of the polymer refers to modulus changing and heat conversion during the shape morphing, and a thermal tunable tribological was observed based on the physicochemical properties varying of polymer with temperature changing. The shape memory effect of BPEPs drives the wear self-compensation so that a low wear rate (6.94 × 10−5 mm3 N−1 m−1) at 110 °C was obtained. The superb lubricating properties of this BPEP could broaden the application scope of shape memory polymers in the field of intelligent lubricating materials, and it is expected to guide future studies on the thermal regulating of tribological behavior. [ABSTRACT FROM AUTHOR]

Near‐infrared (NIR) light responsive shape memory polymers (SMPs) can realize remotely and regionally controlled shape changing that shows broad potential applications. Herein, an NIR‐responsive shape memory polymer (G/PNs) is prepared by introducing reduced graphene oxide to liquid crystal elastomers‐based polymer networks (PNs). The G/PNs present regulated reversible stress by tuning the NIR light irradiation. Furthermore, since the G/PNs are 3D‐printed with designed structure, the deformed 3D printing structure can be regionally patterned with varied shapes by controlling the moving path of NIR laser. In addition, the stress relaxation and cyclic stress–strain measurements are further studied to reveal the energy loss during the deformation and shape memory cycles. In compare with the previous work, the SMP networks provide a rather high reversible actuation stress and can realize remotely control by NIR. The NIR‐encoded shape memory effect can be used as actuators, artificial muscles. [ABSTRACT FROM AUTHOR]

Shape memory epoxy resin (SMEP) with tailorable properties has gained wide attention. Herein, a series of photocured diphenyl epoxy with excellent shape memory effects, based on the epoxy monomer diglycidyl ether of biphenyl (DGEBP) and M‐xylylenediamine (MXDA), is fabricated. Fourier transform infrared spectrometer (FTIR) is used to verify the mix‐curing process. Differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), polarized light microscope (POM), and X‐ray diffraction (XRD) are applied to analyze the microstructure of the film. The molar ratio of the raw material and the post‐heating could tune the crosslinking density, which allows the prepared epoxy resin to present a tailorable shape memory effect. Besides, this epoxy resin exhibits an excellent triple‐shape memory effect due to the wide transition temperature. It is worth of noting that post‐heating induced the self‐assembly of biphenyl unit of the lamellar structure due to π–π interactions that causes an adjustable shape memory effect. This work offers a novel SMEP with potential application in the thermal history trace field. [ABSTRACT FROM AUTHOR]

The 4D‐printing technology is applied to fabricate a shape memory peripheral stent with good biocompatibility, which sustains long‐term drug release. The star polymer s‐PCL is prepared by ring opening polymerization of ε‐caprolactone with the ‐OH of β‐cyclodextrin (βCD) as initiator, and then the s‐PCL is modified with acrylate endgroup which allows the polymerization under UV light to form the crosslinking network c‐PCL. Attributed to the feature of the high crosslinked structure and chemical nature of polycaprolactone (PCL) and βCD, the composite exhibits appropriate tensile strength and sufficient elasticity and bursting pressure, and it is comparable with great saphenous vein in human body. The radial support of the 4D‐printed stent is 0.56 ± 0.11 N and is equivalent to that of commercial stent. The cell adhesion and proliferation results show a good biocompatibility of the stent with human umbilical vein endothelial cells. Due to the presence of βCD, the wettability and biocompatibility of the materials are improved, and the sustained paclitaxel release based on the host–guest complexion shows the potential of the drug‐loaded stent for long‐term release. This study provides a new strategy to solve the urgent need of small‐diameter scaffolds to treat critical limb ischemia. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biodegradable Filters based on copolymer of Poly(glycerol sebacate) acrylate- co -hydroxyethyl methacrylate were 4D printed. • The filters with suitable transition temperatures and mechanical properties as deployable medical devices. • The copolymer presented excellent cytocompatibility, hemocompatibility and histocompatibility. • The simulated deployment of implants and intercepted of thrombus indicated the clinical feasibility of 4D printing filters. Biodegradable shape memory polymers (SMP) with suitable transition temperatures (T r) and mechanical properties are highly demanded in biomedical field as deployable medical devices. Herein, we report a 4D printing shape memory Inferior Vena Cava Filters (IVCFs), an implantation device, which could prevent the fatal pulmonary embolism, to exemplify the applicability of the biodegradable shape memory polymer in biomedical device field. The IVCF composed of poly(glycerol sebacate) acrylate- co -hydroxyethyl methacrylate (PGSA- co -HEMA) was digital light processing (DLP) 3D printed. The appropriate mechanical property and T r = 37.8 °C, which is close to human body temperature, was tailored by tuning the ratio of the raw material. PGSA-PHEMA presents an excellent cytocompatibility, hemocompatibility and histocompatibility as implants. Besides, in vitro degradation results indicate the biodegradability but withhold the mechanical properties within the service time. Furthermore, the simulated filter deploying and fully emboli interception verifies the successful realization of the concept of rapid, minimally invasive and controllable implantation of the 4D printing of IVCFs through the SMP transformation process, and the feasibility of the filter as well. Therefore, this work provides a new biocompatible SMP and offers a new strategy for developing deployable medical devices. [ABSTRACT FROM AUTHOR]

Shape memory polymer with high transition temperature (T r) is highly demanded in many fields. A cyanate ester (CE) based shape memory polymer with tunable T r and excellent mechanical property was prepared by using CE, carboxy-terminated liquid nitrile rubber (CTBN) and epoxy resin (E51 or GE36) in this work. The rheological behavior and fourier transformation infrared spectrogram results indicate the addition of CTBN containing of carboxylate could accelerate the triazine forming and reduce the curing temperature. Adding CTBN and epoxy resin to CE resulted in the formed network with reduced triazine density that the toughness was significantly improved, the elongation at break can reach up to 40%. The T r , mechanically property could be tuned in a larger range by adjusting the ratio between CE, CTBN and epoxy resin. The shape memory cyanate ester (SMCE) presented an excellent shape memory effect even a triple shape memory effect. This work provides a promise shape memory material for broad applications. [Display omitted] • A cyanate ester (CE) based shape memory polymer with tunable T g and excellent mechanical property was prepared. • Adding carboxy-terminated liquid nitrile rubber and epoxy resin to CE resulted in the toughness significantly improving. • The shape memory cyanate ester (SMCE) presented an excellent shape memory even a triple shape memory effect. [ABSTRACT FROM AUTHOR]

• Hyperbranched polyurethane was applied through grafting epoxy resin to obtain interpenetrating polymer networks. • Crosslinking network points help enhancing thermal and mechanical properties. • All interpenetrating polymer networks express excellent shape memory effect. In this article, a type of hyperbranched polyurethane (HBPU) with triazine structure was successfully synthesized. Afterwards, HBPU was applied through grafting epoxy resin (EP) to fabricate the interpenetrating polymer networks (IPNs) with different ratio of HBPU/EP. The structure of HBPU prepolymer and the formation of the HBPU/EP IPNs were characterized and confirmed by Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared (FTIR) spectroscopy, and the nanoscale phase separation in IPNs composite was analyzed by Atomic Force Microscope (AFM). Besides, the thermal and mechanical results indicated that the IPNs structure enables the material with high strength and thermal stability. Shape memory cycles test demonstrated that the HBPU/EP INPs possess an excellent shape memory performance, and the best shape fixity and recovery were presented by IPNs composite with 20 wt% HBPU. [ABSTRACT FROM AUTHOR]