Mechanically Tough, Thermally Activated Shape Memory Hydrogels

Hao, Jinkun; Weiß, Robert

doi:10.1021/mz3006389

Cited by 131 publications

(107 citation statements)

References 18 publications

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“…As such, a temporary shape can be fixed upon deformation via cooling from above its melting temperature to room temperature. This, and other early examples of shape memory hydrogels rely on thermal reversible phase changes as the phase switches and their recovery is typically induced thermally [121][122][123][124]. As has been laid out in an earlier section, the concept of molecular switches has unparallel advantages in designing solid SMPs.…”

Section: Shape Memory Hydrogelsmentioning

confidence: 97%

Recent progress in shape memory polymer: New behavior, enabling materials, and mechanistic understanding

Zhao

Xie

2015

Progress in Polymer Science

1,191

749

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Shape memory polymers (SMPs), as a class of programmable stimuliresponsive shape changing polymers, are attracting increasing attention from the standpoint of both fundamental research and technological innovations. Following a brief introduction of the conventional shape memory effect (SME), progress in new shape memory enabling mechanisms and triggering methods, variations of in shape memory forms (shape memory surfaces, hydrogels, and microparticles), new shape memory behavior (multi-SME and two-way-SME), and novel fabrication methods are reviewed. Progress in thermomechanical modeling of SMPs is also presented. Abbreviations:SCPs shape changing polymers; LCEs liquid crystalline elastomers; SMP shape memory polymer; SME shape memory effect; 2W two-way; 1W oneway; T trans transition temperature; T g glass transition temperature; T m melting temperature; T cl liquid crystal cleaning temperature; T d deformation temperature; T f shape fixing temperature; T c crystallization temperature; R f shape stability ratio; R r shape recovery ratio; T sw switching temperature; ε max maximum recoverable strain; σ max maximum recovery stress; SMC shape memory cycle; ε load strain under load; ε fixed strain; T r recovery Page 2 of 106 A c c e p t e d M a n u s c r i p t 2 temperature; ε rec recovered strain; V r strain recovery rate; T σmax temperature corresponding to σ max ; T sw,app apparent switching temperature; PCL poly(ε-caprolactone); SMPU shape memory polyurethane; EMU elemental memory unit; TME temperature memory effect; PU polyurethane; T i liquid-crystal isotropic transition temperature; T v vitrification temperature; CIE crystallization induced elongation; MIC melting induced contraction

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Section: Shape Memory Hydrogelsmentioning

confidence: 97%

Recent progress in shape memory polymer: New behavior, enabling materials, and mechanistic understanding

Zhao

Xie

2015

Progress in Polymer Science

1,191

749

View full text Add to dashboard Cite

show abstract

“…Hao and Weiss have built on this work by developing a thermoresponsive shape memory hydrogel that switches between two flexible states, allowing for exploitation of soft and hydrophilic material properties both below and above the switching temperature. [15] This quad-polymer material was shown to effectively fix and recover shape, triggered by changes in temperature, and retain flexibility, hydrophilicity, and mechanical toughness throughout. Li and co-workers have extended the range of potential transition mechanisms in shape memory hydrogels by incorporating light and pH-triggered switches, in addition to thermally triggered switches, into their materials.…”

Section: Engineered Assembly Of Bioinspired Materialsmentioning

confidence: 99%

Biomimicry, Biofabrication, and Biohybrid Systems: The Emergence and Evolution of Biological Design

Raman

Bashir

2017

Adv Healthcare Materials

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how the concept of bioinspiration, or imitating biological design and functionality in synthetic materials, created a new class of "smart" biomimetic materials. Then, we shall discuss how the continuing development of enabling manufacturing technologies, such as 3D printing and microfluidics, has established the separate subdiscipline of biofabrication for tissue engineering, or "building with biology." Finally, we shall investigate the convergence of these two fields into the emerging discipline of biohybrid design, the use of biological materials to power non-natural functional behaviors in synthetic machines. Throughout this report, we will revisit a single class of materials, hydrogels, as a case study of biological design in the context of each subfield, and discuss how the constraints, underlying principles, and end-use applications differ in each case. We will also discuss ethical considerations of biological design, with a special focus on forward engineering non-natural or hypernatural functional behaviors in biohybrid systems. We will conclude with recommendations for implementing biological design into educational curricula, ensuring effective and responsible practices for the next generation of engineers and scientists. Biomimicry and Bioinspired DesignA deeper understanding of the underlying design principles that govern biological systems has inspired the field of biomimicry. [1,2] Observing adaptive phenomena in nature, scientists and engineers have sought to extract the components of biological design responsible for this behavior and replicate the behavior in synthetic materials. Fundamentally, this involves understanding the building blocks or base units from which a biological material is built, the hierarchical assembly of these building blocks, and the interactions and interfaces between them.In this section, we will discuss strategies that engineers and scientists have employed to engineer bioinspired hierarchy, from bottom-up self-assembly and top-down engineered assembly. We will present several key demonstrations of stimulus-responsive hydrogels ranging from the micro-to the macroscale, and investigate novel demonstrations in biomimetic actuation and movement. We will conclude with the remaining challenges in the field of biomimicry and discuss the potential future impact of bioinspired design.The discipline of biological design has a relatively short history, but has undergone very rapid expansion and development over that time. This Progress Report outlines the evolution of this field from biomimicry to biofabrication to biohybrid systems' design, showcasing how each subfield incorporates bioinspired dynamic adaptation into engineered systems. Ethical implications of biological design are discussed, with an emphasis on establishing responsible practices for engineering non-natural or hypernatural functional behaviors in biohybrid systems. This report concludes with recommendations for implementing biological design into educational curricula, ensuring effective and responsible practice...

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“…Stimuli‐responsive polymeric materials have the ability to program shape changes in response to cues from their environment so that they have potential applications in micromachines, soft robots, and biomedical systems. A variety of intelligent polymeric materials such as liquid crystal elastomers (LCEs), shape memory polymers, hydrogels, conducting polymers, and dielectric elastomers have been developed in recent years due to their wide applications …”

Section: Introductionmentioning

confidence: 99%

Liquid Crystal Elastomer Actuators from Anisotropic Porous Polymer Template

Wang

et al. 2017

Macromol. Rapid Commun.

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Controlling self-assembly behaviors of liquid crystals is a fundamental issue for designing them as intelligent actuators. Here, anisotropic porous polyvinylidene fluoride film is utilized as a template to induce homogeneous alignment of liquid crystals. The mechanism of liquid crystal alignment induced by anisotropic porous polyvinylidene fluoride film is illustrated based on the relationship between the alignment behavior of liquid crystals and surface microstructure of anisotropic polyvinylidene fluoride film. Liquid crystal elastomer actuators with fast responsiveness, large strain change, and reversible actuation behaviors are achieved by the photopolymerization of liquid crystal monomer in liquid crystal cells coated with anisotropic porous films.

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Mechanically Tough, Thermally Activated Shape Memory Hydrogels

Cited by 131 publications

References 18 publications

Recent progress in shape memory polymer: New behavior, enabling materials, and mechanistic understanding

Recent progress in shape memory polymer: New behavior, enabling materials, and mechanistic understanding

Biomimicry, Biofabrication, and Biohybrid Systems: The Emergence and Evolution of Biological Design

Liquid Crystal Elastomer Actuators from Anisotropic Porous Polymer Template

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