Thermo-moisture responsive polyurethane shape-memory polymer and composites: a review

Huang, Wei; Yang, Bin; Zhao, Yong; Ding, Zheng

doi:10.1039/b922943d

Cited by 353 publications

(218 citation statements)

References 58 publications

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“…47 Reporting nanocomposites based on a rubbery polyurethane matrix and cellulose nanowhiskers isolated from cotton, we show here that the combination of the above-described approach to water-triggered mechanically adaptive behavior with a highly elastic polymer matrix is the basis for a shape-memory effect that uses water as a stimulus. While the reinforcement of polyurethanes with short cellulose nanowhiskers has been described before, 50À53 the here-reported shape-memory is unprecedented and offers attributes that are especially attractive for biomedical applications, 11 such as self-tightening sutures, self-retractable and removable stents, and porous materials with adjustable pore size.…”

Section: Methodsmentioning

confidence: 99%

“…One design approach for such materials relies on the reduction of the glass transition temperature (T g ) of thermoresponsive shape-memory polyurethanes by way of plasticization upon immersion in water; here, the fixation of the temporary shape involved deformation at elevated temperature and cooling below T g . 10,11,31 Recently a purely solvent-induced shape-memory effect was also reported for a chemically cross-linked polyvinyl alcohol. 12,13 ABSTRACT: New biomimetic, stimuli-responsive mechanically adaptive nanocomposites, which change their mechanical properties upon exposure to water and display a water-activated shape-memory effect, were investigated.…”

Section: Methodsmentioning

confidence: 99%

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Bioinspired Mechanically Adaptive Polymer Nanocomposites with Water-Activated Shape-Memory Effect

et al. 2011

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' INTRODUCTION Materials1À4 that can be manipulated to a "fixed" temporary shape and reverted later to the "memorized" original shape upon exposure to an external stimulus such as heat, 1À3 light, 5À7 magnetic fields, 8,9 or chemicals 10À13 are useful for a plethora of potential applications that range from mechanically adaptive materials for biomedical devices 2,14À18 to aerospace structures 18,19 to dry adhesives 20 to optical devices. 21 Polymers intrinsically show shapememory effects, on the basis of rubber elasticity, but with varied characteristics of strain recovery rate, work capability during recovery, and retracted state stability. The elasticity can be imparted by covalent or physical cross-links. The polymer is typically deformed in its rubbery state above a transition temperature (T trans ), i.e., either glass transition, crystallization, or melting temperature, is cooled to below the transition temperature (T trans ) to fix a temporary shape in which the energy used for deformation is stored. Later, the recovery to its original shape is driven by regaining the entropy lost during deformation. 22 The ability to fix temporary shapes depends mainly on the possibility to create discrete reversible phase transitions in the polymer. 23À26 Thus, a broad range of different shape-memory polymers has been or can be developed, which exploit various reversible phase transitions and are designed to respond to different external stimuli. The most widely studied behavior is a purely thermally induced shape-memory effect, which relies on heating to above and cooling to below a transition temperature; indirect heating upon exposure of appropriately modified systems to an electrical current, magnetic field, or light represent interesting variations of this approach. 27À30 A light-induced shape-memory effect was also demonstrated, which was achieved by introducing photoresponsive cinnamic acid units into acrylate hydrogels. This allows one to trigger the shape-memory effect with light under isothermal conditions. 5 Comparably few materials have been described in which the shape-memory recovery can be triggered by a chemical stimulus. One design approach for such materials relies on the reduction of the glass transition temperature (T g ) of thermoresponsive shape-memory polyurethanes by way of plasticization upon immersion in water; here, the fixation of the temporary shape involved deformation at elevated temperature and cooling below T g . 10,11,31 Recently a purely solvent-induced shape-memory effect was also reported for a chemically cross-linked polyvinyl alcohol. 12,13ABSTRACT: New biomimetic, stimuli-responsive mechanically adaptive nanocomposites, which change their mechanical properties upon exposure to water and display a water-activated shape-memory effect, were investigated. These materials were produced by introducing rigid cotton cellulose nanowhiskers (CNWs) into a rubbery polyurethane (PU) matrix. A series of materials with CNW concentrations of 2À20% v/v was produced by solution blending CNWs an...

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Bioinspired Mechanically Adaptive Polymer Nanocomposites with Water-Activated Shape-Memory Effect

et al. 2011

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“…There is no apparent volume expansion at all and according to Figure 8, in terms of weight percent, the absorbed water is less than 5%. Furthermore, Figure 8 reveals that the absorbed water has two parts, one part is free water which does not have significant effect on the T g and can be removed upon heating to less than 120 °C, while the other part is bound water, which can reduce the T g remarkably (up to 30 °C) and can only be removed upon heating to above 120 °C [20]. In addition to water, ethanol is another chemical which can trigger the chemo-responsive SME in PU, and in a much higher speed [102].…”

Section: Softeningmentioning

confidence: 99%

“…In the past decade, extensive and continuous research efforts have been devoted to developing new polymers with the SME and/or improving the existing ones for higher performance [14,[19][20][21][22][23][24][25][26][27][28][29][30]. On the other hand, a few new shape memory phenomena have been discovered [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47], which not only enhance the flexibility of the current shape memory technology, but also add in new dimensions for extended versatility and adoptability.…”

Section: Figurementioning

confidence: 99%

Mechanisms of the Shape Memory Effect in Polymeric Materials

et al. 2013

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Abstract:This review paper summarizes the recent research progress in the underlying mechanisms behind the shape memory effect (SME) and some newly discovered shape memory phenomena in polymeric materials. It is revealed that most polymeric materials, if not all, intrinsically have the thermo/chemo-responsive SME. It is demonstrated that a good understanding of the fundamentals behind various types of shape memory phenomena in polymeric materials is not only useful in design/synthesis of new polymeric shape memory materials (SMMs) with tailored performance, but also helpful in optimization of the existing ones, and thus remarkably widens the application field of polymeric SMMs.

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“…This external stimulus can be temperature [18,19], magnetism [20][21][22], moisture [23], or light [18,24].…”

Section: Shape Memory Materialsmentioning

confidence: 99%

Smart Delivery Systems with Shape Memory and Self-Folding Polymers

Erkeçoğlu¹,

Sezer²,

Bucak³

2016

Smart Drug Delivery System

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New generation delivery systems involve smart materials such as shape memory and self-folding polymers. Shape memory polymers revert back to their original shape above their glass transition temperatures where this temperature change can be induced conventionally, photolytically, with a lazer or magnetically depending on the composition of the material. This ability to assume original shape upon a trigger can be used in delivering drugs, DNA or cells. Self folding polymers are a new class of materials which may be composed of multilayers with different thermal expansion coefficients or with hinges that allow folding upon being triggered. These new materials allow various architectural designs of smart delivery vehicles predominantly for DNA and cells. The aim of this chapter is given shape and folding polymers and their usage for drug delivery systems.

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Thermo-moisture responsive polyurethane shape-memory polymer and composites: a review

Cited by 353 publications

References 58 publications

Bioinspired Mechanically Adaptive Polymer Nanocomposites with Water-Activated Shape-Memory Effect

Bioinspired Mechanically Adaptive Polymer Nanocomposites with Water-Activated Shape-Memory Effect

Mechanisms of the Shape Memory Effect in Polymeric Materials

Smart Delivery Systems with Shape Memory and Self-Folding Polymers

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