Poor, nontunable mechanical properties as well as finite shape memory performance pose a barrier to shape memory hydrogels to realize practical applications. Here, a new shape memory hydrogel with tunable mechanical properties and multishape memory effect was presented. Three programmable reversible systems including PBA-diol ester bonds, AAc-Fe, and coil-helix transition of agar were applied to memorize temporary shapes and endow the hydrogel with outstanding multishape memory functionalities. Moreover, through changing the cross-linking densities, the mechanical properties of the as-prepared hydrogel can be adjusted.
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http://dx.doi.org/10.1021/acsami.7b00169 | DOI Listing |
Adv Mater
September 2024
State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310058, China.
Shape memory polymers (SMPs) show attractive prospects in emerging fields such as soft robots and biomedical devices. Although their typical trigger-responsive character offers the essential shape-changing controllability, having to access external stimulation is a major bottleneck toward many applications. Recently emerged autonomous SMPs exhibit unique stimuli-free shape-shifting behavior with its controllability achieved via a delayed and programmable recovery onset.
View Article and Find Full Text PDFACS Appl Mater Interfaces
November 2023
Ningbo Innovation Center, Zhejiang University, Ningbo 315100, China.
The combination of three-dimensional (3D) printing and shape memory polymers (SMP) enables programmable shape morphing of complex 3D structures, which is commonly termed four-dimensional (4D) printing. The process requirements of vat photopolymerization-based 3D printing impose limitations on the molecular structure design of SMPs, making it challenging to achieve triple- or multiple-shaped memory effects. Herein, we printed SMPs with different values and obtained an SMP assembly through interfacial welding.
View Article and Find Full Text PDFNat Commun
September 2023
The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
Shape-morphing structures that can reconfigure their shape to adapt to diverse tasks are highly desirable for intelligent machines in many interdisciplinary fields. Shape memory polymers are one of the most widely used stimuli-responsive materials, especially in 3D/4D printing, for fabricating shape-morphing systems. They typically go through a hot-programming step to obtain the shape-morphing capability, which possesses limited freedom of reconfigurability.
View Article and Find Full Text PDFACS Macro Lett
July 2023
Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong 518060, China.
Tunable multishape memory polymers offer intriguing opportunities for memorizing multiple temporary shapes with tunable transition temperatures from one material composition. However, such multishape memory effects have been exclusively correlated with the thermomechanical behaviors of polymers, significantly limiting their applications in heat-sensitive scenarios. Here we report a nonthermal tunable multishape memory effect in covalently cross-linked cellulosic macromolecular networks, which spontaneously organize into supramolecular mesophases by water evaporation induced self-assembly.
View Article and Find Full Text PDFACS Appl Mater Interfaces
October 2022
Henan Key Laboratory of Photovoltaic Materials, Henan University, Kaifeng475004, P. R. China.
Benefiting from the associative exchange reaction, vitrimers could be deformed to various shapes while maintaining the integrity of the network, thus being regarded as promising candidates for shape memory polymers. However, it is still a challenge to design the highly desired smart electronic devices with triple and multishape memory performances through a facile method. Here, a novel dual-cross-linked poly(acrylonitrile--butyl acrylate--hydroxyethyl methacrylate--zinc methacrylate) (Zn-PABHM) copolymer was developed via a facile and one-pot free radical polymerization strategy.
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