Thermal- and pH-responsive triple-shape memory hydrogel based on a single reversible switch

Song, Yufang; Liu, Hui; Wang, Xiaorong; Chen, Yi-Ming; Zhong, Weifeng; Wang, Dong; Shi, Dongjian; Yang, Wei; Ma, Piming; Zhang, Hongji

doi:10.1039/d3sm00670k

Cited by 5 publications

(4 citation statements)

References 27 publications

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“…Beyond their outstanding mechanical properties, 44–47 the dynamic nature of hydrogen bonds also confers the magnetic hydrogels with brilliant shape memory properties. 48–51 To quantitatively characterize the shape memory performance, a rectangle hydrogel strip is softened and bent to a “U” shape in hot water (10 degrees above T g ), and then fixed in cold water (10 °C). The hydrogel readily recovers to the original shape after being placed in hot water.…”

Section: Resultsmentioning

confidence: 99%

Magnetic-field induced shape memory hydrogels for deformable actuators

Tian,

Xu,

et al. 2024

Soft Matter

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Section: Resultsmentioning

confidence: 99%

Magnetic-field induced shape memory hydrogels for deformable actuators

Tian,

Xu,

et al. 2024

Soft Matter

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“…This may expand the application of the phase-change composites into soft actuators and control devices. 27−31 According to the phase-transition and thermoviscoelastic theories, shape memory materials have two structural components, i.e., the reversible switching phase and permanent phase, 32,33 which can serve as adaptive programmable materials for flexible devices. 34,35 Solid−liquid PCMs can act as the reversible switching phase to drive shape memory transitions through solid−liquid phase changes.…”

Section: ■ Introductionmentioning

confidence: 99%

“…In contrast to inorganic foams, the utilization of elastic polymer foams as support materials for organic PCMs can endow the resultant phase-change composites with shape memory properties. This may expand the application of the phase-change composites into soft actuators and control devices. − According to the phase-transition and thermoviscoelastic theories, shape memory materials have two structural components, i.e., the reversible switching phase and permanent phase, , which can serve as adaptive programmable materials for flexible devices. , Solid–liquid PCMs can act as the reversible switching phase to drive shape memory transitions through solid–liquid phase changes. When the environmental temperature is higher than the melting temperature ( T m ) of a solid–liquid PCM, the PCM is melted to obtain a softened state, resulting in its deformation to a certain shape.…”

Section: Introductionmentioning

confidence: 99%

Eco-Friendly Flame-Retardant Phase-Change Composite Films Based on Polyphosphazene/Phosphorene Hybrid Foam and Paraffin Wax for Light/Heat-Dual-Actuated Shape Memory

Zhou,

Liu,

Zhang

et al. 2024

ACS Appl. Mater. Interfaces

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Multiactuated shape memory materials are a class of promising intelligent materials that have received great interest in the fields of self-healing, anticounterfeiting, biomedical, soft robotic, and smart thermal management applications. To obtain a light/heat-dual-actuated shape memory material for thermal management applications in fire safety, we have designed a type of halogen-free flame-retardant phase-change composite film based on polyaryloxyphosphazene (PDAP)/phosphorene (PR) hybrid foam as a support material and paraffin wax (PW) as a phase-change material (PCM). PDAP was synthesized as a flexible foam matrix through the ring-opening polymerization of hexachlorocyclotriphosphazene, followed by a substitution reaction of aryloxy groups. The porosity of the PDAP foam is improved by introducing PR nanosheets, facilitating a high latent heat capacity of the PDAP−PR/PW composite films for thermal management applications. The PDAP−PR/PW composite films can implement rapid shape recovery within 65 s in the heating process, which is much shorter than that of the corresponding film without PR nanosheets (185 s). Furthermore, the PDAP−PR/PW composite films also exhibit light-actuated shape memory behavior thanks to their good solar-tothermal energy absorption and conversion contributed by PR nanosheets as a highly effective photothermal material. More importantly, the presence of PR nanosheets imparts an excellent flame-retardant property to the PDAP−PR/PW composite films. The PDAP−PR/PW composite film can be self-extinguished within 2 s after the flame. Through an innovative integration of flexible polyphosphazene foam, PR nanosheets, and solid−liquid PCM to obtain a sensitive actuating response to light and heat, this study offers a new approach for developing multiactuated and eco-friendly flame-retardant shape memory materials to meet the requirement of applications with a requirement of fire safety in soft actuators, thermal therapy, control devices, and so on.

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“…Nevertheless, the discontinuous transition was not the primary focus of the previous work, and so the encapsulated microbubble volume fraction dependence of the observed discontinuous behavior, as well as the underlying physics, are still unknown. Gaining an understanding of such discontinuous behavior is important as hydrogels have received much attention owing to their ability, in part, to be used as building blocks in wearable sensors 4 , reversible switches 19 , and for their potential use in implantable microdevices with moving parts 7 , 8 . In this regard, the ability to remotely induce an abrupt transition within a gel’s properties could serve as a key component in such systems if the transition could be used as an actuator for moving parts or lead to switch-like behavior in material properties.…”

Section: Introductionmentioning

confidence: 99%

Unconventional acoustic wave propagation transitions induced by resonant scatterers in the high-density limit

Matis,

Liskey,

Gangemi

et al. 2024

Sci Rep

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Experiments on ultrasound propagation through a gel doped with resonant encapsulated microbubbles provided evidence for a discontinuous transition between wave propagation regimes at a critical excitation frequency. Such behavior is unlike that observed for soft materials doped with non-resonant air or through liquid foams, and disagrees with a simple mixture model for the effective sound speed. Here, we study the discontinuous transition by measuring the transition as a function of encapsulated microbubble volume fraction. The results show the transition always occurs in the strong-scattering limit (l/λ < 1, l and λ are the mean free path and wavelength, respectively), that at the critical frequency the effective phase velocity changes discontinuously to a constant value with increasing microbubble volume fraction, and the measured critical frequency shows a power law dependence on microbubble volume fraction. The results cannot be explained by multiple scattering theory, viscous effects, mode decoupling, or a critical density of states. It is hypothesized the transition depends upon the microbubble on-resonance effective properties, and we discuss the results within the context of percolation theory. The results shed light on the discontinuous transition’s physics, and suggest soft materials can be engineered in this manner to achieve a broad range of physical properties with potential application in ultrasonic actuators and switches.

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Thermal- and pH-responsive triple-shape memory hydrogel based on a single reversible switch

Abstract: Here we provide a novel method for fabricating pH- and thermal-responsive triple-shape memory hydrogel based on a single reversible switch phase. A high-density quadruple hydrogen-bonding ureido-pyrimidinone (UPy) system was introduced...

Cited by 5 publications

References 27 publications

Magnetic-field induced shape memory hydrogels for deformable actuators

Magnetic-field induced shape memory hydrogels for deformable actuators

Eco-Friendly Flame-Retardant Phase-Change Composite Films Based on Polyphosphazene/Phosphorene Hybrid Foam and Paraffin Wax for Light/Heat-Dual-Actuated Shape Memory

Unconventional acoustic wave propagation transitions induced by resonant scatterers in the high-density limit

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