Design of Autonomous Gel Actuators

Maeda, Shingo; Hara, Yusuke; Nakamaru, Satoshi; Hashimoto, Shuji

doi:10.3390/polym3010299

Cited by 8 publications

(2 citation statements)

References 35 publications

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“…For spontaneous and reversible alternation between the original and temporary shapes, the hydrogels are usually designed with anisotropic structures via special reactions, such as bilayer or multilayer lamella, anisotropic crosslinking network, patterned structure,[3f,13] and Belouzov–Zhabotinsky vibration . These systems can accomplish actuations automatically under certain stimuli through transferring the isotropic volume expansion into anisotropic movements.…”

Section: Introductionmentioning

confidence: 99%

Polyampholyte Hydrogels with pH Modulated Shape Memory and Spontaneous Actuation

Zhang

Liao

Wang

et al. 2018

Adv Funct Materials

167

133

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Polyampholyte hydrogels are synthesized by one-step copolymerization of cationic monomer 3-(methacryloylamino)propyltrimethylammonium chloride, anionic monomers sodium p-styrenesulfonate (NaSS), and methacrylic acid (MAA) without chemical crosslinker and adding salts. The hydrogels exhibit pH responsive shape memory behavior; the temporary shape of the hydrogel is formed manually after immersing in NaOH solution and fixed in HCl solution, while the shape recovery occurs by immersing in NaOH again. Most interestingly, the hydrogel shows a spontaneous shape change after the first shape memory cycle. When the recovered hydrogel with a little residual deformation is immersed in HCl again, it twists spontaneously and rapidly to the previous temporary shape. The spontaneous twisting and recovering can be repeated for ten times. Furthermore, the hydrogel swells quickly and is strengthened in HCl, while shrinks and weakens in NaOH during the shape change procedure. This unique synergistic effect of fast swelling, residual helical deformation, and increased strength plays a significant role in the spontaneous shape alternation. This new finding will initiate a new prosperous design for new soft actuators requiring successive actions.

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Section: Introductionmentioning

confidence: 99%

Polyampholyte Hydrogels with pH Modulated Shape Memory and Spontaneous Actuation

Zhang

Liao

Wang

et al. 2018

Adv Funct Materials

167

133

View full text Add to dashboard Cite

show abstract

“…13 Autonomously moving gels have been actuated and simulated using the oscillating Belousov-Zhabotinsky reaction, which induces shrinking or swelling in specic regions of the gel network. [14][15][16] Stimulating the motion of hydrogels using external electrical elds is appealing due to the reliable control of the signal strength and direction. This stimulus only requires ions to be present in the external solution to induce actuation.…”

Section: Introductionmentioning

confidence: 99%

Electro-actuated hydrogel walkers with dual responsive legs

et al. 2014

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Stimuli responsive polyelectrolyte hydrogels may be useful for soft robotics because of their ability to transform chemical energy into mechanical motion without the use of external mechanical input. Composed of soft and biocompatible materials, gel robots can easily bend and fold, interface and manipulate biological components and transport cargo in aqueous solutions. Electrical fields in aqueous solutions offer repeatable and controllable stimuli, which induce actuation by the re-distribution of ions in the system. Electrical fields applied to polyelectrolyte-doped gels submerged in ionic solution distribute the mobile ions asymmetrically to create osmotic pressure differences that swell and deform the gels. The sign of the fixed charges on the polyelectrolyte network determines the direction of bending, which we harness to control the motion of the gel legs in opposing directions as a response to electrical fields. We present and analyze a walking gel actuator comprised of cationic and anionic gel legs made of copolymer networks of acrylamide (AAm)/sodium acrylate (NaAc) and acrylamide/quaternized dimethylaminoethyl methacrylate (DMAEMA Q), respectively. The anionic and cationic legs were attached by electric field-promoted polyion complexation. We characterize the electro-actuated response of the sodium acrylate hydrogel as a function of charge density and external salt concentration. We demonstrate that "osmotically passive" fixed charges play an important role in controlling the bending magnitude of the gel networks. The gel walkers achieve unidirectional motion on flat elastomer substrates and exemplify a simple way to move and manipulate soft matter devices and robots in aqueous solutions.

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Polymer Gels

Philippova

Khokhlov

2012

Polymer Science: A Comprehensive Reference

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Design of Autonomous Gel Actuators

Cited by 8 publications

References 35 publications

Polyampholyte Hydrogels with pH Modulated Shape Memory and Spontaneous Actuation

Polyampholyte Hydrogels with pH Modulated Shape Memory and Spontaneous Actuation

Electro-actuated hydrogel walkers with dual responsive legs

Polymer Gels

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