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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]

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] • The highest tensile strength of 3D printing SMP was obtained. • A SMCE could be prepared through DLP or DIW mode 3D printing. • The new 3D printing strategy shows high printing resolution. • The printed IPN structure exhibits extremely low volume contraction. • The 4D printing SMP demonstrated a variety of applications. 3D printing shape memory polymers (SMP) with high strength and high transition temperature (T r) are widely demanded in many fields, such as the aerospace material. However, either the SMP with high T r or the 3D printing such polymer remains challenging. Here, a cyanate ester based shape memory interpenetrating polymer network (IPN) was prepared successfully through both of digital light process (DLP) and direct ink writing (DIW) 3D printing. Significantly, the 3D printed shape memory polymer performs a highest reported tensile strength of 3D printing SMPs, which is up to 70 MPa. Besides, the high printing resolution and low volume contraction, the high T r (about 170 °C), high modulus, and excellent shape memory effect (with average shape fixation ratio (>95%), and average shape recovery ratio (>86%)) allows the 3D printing SMP to perform a versatile applicability. The application of this 3D printing SMP was demonstrated by spiral spring with high modulus, deformable sealing ring for easy installation, and smart mold for the manufacturing of fiber composite with complex structure. This work provides a preparing strategy for 3D printing cyanate ester based SMP, which could be applied in broad fields. [ABSTRACT FROM AUTHOR]