Shape memorizing properties of a hydrogel of poly(vinyl alcohol)

Hirai, Toshihiro; Maruyama, Hidetoshi; Suzuki, Takashi; Hayashi, Sadao

doi:10.1002/app.1992.070451019

Cited by 82 publications

(58 citation statements)

References 7 publications

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“…As melting of ordered phase. [9][10][11][12] It is well-known that the heat-triggered SM in dry-state polymers relies on reversible thermal transitions (e.g., a glass transition or melting transition). For water-fi lled hydrogel network, Tg loses its efficacy in fabricating SM hydrogels due to the plasticization and hydration from a large amount of water molecules.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Zinc Ion Uniquely Induced Triple Shape Memory Effect of Dipole–Dipole Reinforced Ultra‐High Strength Hydrogels

Han

Bai

Liu

et al. 2011

Macromol. Rapid Commun.

111

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In this study, we demonstrate that dipole-dipole interaction can be employed to not only tremendously enhance the mechanical properties of hydrogel, but also impart the gel to an amazing ability to memorize two temporary shapes. Cross-linked hydrogels synthesized by copolymerization of acrylonitrile, a dipole-dipole containing monomer and hydrophilic comonomer are shown to exhibit triple shape memory (SM) triggered by the dynamic association and dissociation of dipole-dipole pairing between cynao groups uniquely responding to zinc ion species and concentration. This approach contributes to design and fabrication of novel SM hydrogels in a distinct way from conventional SM materials.

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Section: Resultsmentioning

confidence: 99%

“…

225the hydrogels with SM effect are extremely scarce except for early work on poly(vinyl alcohol) gel [ 9 ] and acrylate copoly mer gel with molecular ordered structure containing long alkyl side chains. [10][11][12] In some articles, other researchers preferred to defi ne swelling and deswelling behavior of hydrogels as two-way SM effect.

…”

mentioning

confidence: 99%

Zinc Ion Uniquely Induced Triple Shape Memory Effect of Dipole–Dipole Reinforced Ultra‐High Strength Hydrogels

Han

Bai

Liu

et al. 2011

Macromol. Rapid Commun.

111

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“…10 -12 Hirai et al have studied the influence of chemical crosslinked structures on the shape-memory behavior of poly(vinyl alcohol) hydrogel. 13,14 Li has introduced the structure of interpenetrating polymer networks (IPNs) to shape-memorized polyacrylamide. 15 In our previous study, the influences of hard segment content 16 and soft segment molecular weight (MW) 17 on the shape-memory behavior of polyether-based PUs were studied.…”

Section: Introductionmentioning

confidence: 99%

Shape-memorized crosslinked ester-type polyurethane and its mechanical viscoelastic model

Lin

Chen

1999

J. Appl. Polym. Sci.

129

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A series of shape-memorized crosslinked ester-type polyurethanes (PUs), based on different compositions of 4,4Ј-diphenyl methane diisocyanate (MDI), poly(butylene adipate) glycol (PBAG) with different molecular weight (MW) and trimethylol propane (TMP), were synthesized. The morphology of samples was investigated by using DSC, WAXD, and dynamic mechanical analysis (DMA). It was found that the morphology of the soft segment, which was PBAG with a different MW, was in an amorphous state and no crystalline domain was found. By increasing the crosslinked density (varying the content of TMP) or decreasing the length of the soft segment (MW of PBAG), the glass transition temperature of studied samples increased. But the range of transition broadened and the modulus ratio EЈ (T g Ϫ20°C) /EЈ (T g ϩ20°C) also decreased. The shape-memory behavior was studied by the bending test method adopted from the shape-memory alloy. The sample with high T g showed not only a high recovered temperature (T r ) but also a high recovered rate (V r ) with a high modulus ratio. By introducing the chemical crosslinked structure, the deformed samples completely recovered their original shape and rendered shape-memory behavior under the complex deformation. The shape-memorized crosslinked ester-type PUs can be applied at different operating temperatures. A mechanical viscoelastic model is discussed for the shape-memory behavior of PUs, and the modified Bonart's viscoelastic model properly describes the mechanism of the shape memory of PUs.

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“…8.6. This localization of the chemical crosslinks gives the gel not only a toughness but a shape memory [19][20][21]. The hydrogel was shrunk in methanol or acetone to remove the water from the gel.…”

Section: Preparation Methods Of the Dmso Gelmentioning

confidence: 99%

Electrically Induced Strain in Polymer Gels Swollen with Non-Ionic Organic Solvents

Hirai¹,

Hirai²

2000

Polymer Sensors and Actuators

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IntroductionPolymer gel actuator has been extensively studied from the standpoints of new intelligent materials. When we define the intelligent material as one that has three functions in a body -sensing, processing, and response or action -polymer gels are adequate as intelligent materials, since they respond by taking various stimuli in the surroundings into account. Polymer gel actuator can be considered, in this sense, as one of the intelligent materials or artificial muscle, which can actuate by sensing various triggers or stimuli to generate strain, taking various factors into account. There has been vast variations of reports on swelling-and-deswelling features induced by changing ionic strength, pH value, solvent composition, and temperature [1][2][3][4][5]. In polyelectrolyte gels, a strain can also be induced by an electric field [6][7][8][9][10]. The electrically induced strain has been considered to be caused principally by electrostatic repulsion or attraction among the ionic species in the gels. The other type of approach is a magnetostrictive action of a ferrofluid immobilizing hydrogel, in which the superparamagnetic properties of the ferrofluid has been utilized and the dispersion mode of the ferro magnetic particles has a serious effect on the strain generation [11][12][13][14][15].Here we will introduce our results on the electrostrictive polymer gels which are swollen with non-ionic organic solvents and which can be actuated by applying an electric field. The gels showed very quick motion compared to the conventional polyelectrolyte gels with application of a direct current electric field. We will show the feature of the action and the structure change of the gel induced by the electric field, discuss the mechanism of the electrostrictive motion of the gels, and make some suggestions to the future development of this type of material. Electrically Induced Strain in PVA-DMSO Gel [16] Electrostrictive Motion of PVA-DMSO GelPoly(vinyl alcohol) gel swollen with dimethylsulfoxide (DMSO) can be actuated by applying an electric field as shown in Fig. 8

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Shape memorizing properties of a hydrogel of poly(vinyl alcohol)

Cited by 82 publications

References 7 publications

Zinc Ion Uniquely Induced Triple Shape Memory Effect of Dipole–Dipole Reinforced Ultra‐High Strength Hydrogels

Zinc Ion Uniquely Induced Triple Shape Memory Effect of Dipole–Dipole Reinforced Ultra‐High Strength Hydrogels

Shape-memorized crosslinked ester-type polyurethane and its mechanical viscoelastic model

Electrically Induced Strain in Polymer Gels Swollen with Non-Ionic Organic Solvents

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