Nano/microstructures of shape memory polymers: from materials to applications

Zhang, Fenghua; Xia, Yuliang; Liu, Yanju; Leng, Jinsong

doi:10.1039/d0nh00246a

Cited by 74 publications

(52 citation statements)

References 164 publications

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“…[ 31 ] Most importantly,

T_{normalg}

of SMP‐based materials can be tuned by varying the synthesis conditions [ 24 ] for a wide range of applications, such as vascular stents, clot removal devices, heart valve repair, and tissue engineering. [ 26,31–35 ] This customization of the material can include the design of various shape‐recovery mechanisms (e.g., pH activation, [ 36 ] moisture, [ 37 ] light triggering, [ 33 ] magnetic remote activation, [ 38 ] and Joule‐heating [ 39 ] ), the tuning of microstructural features, such as porosity and cell shape [ 40,41 ] and number of phase transitions. [ 42 ] This potential for customization, the good biocompatibility of the material, and the low cost of synthesis make SMPs a promising candidate for designing patient‐specific embolic devices with superior occlusion volumes and packing than the conventional Guglielmi detachable coils, [ 43 ] which could potentially resolve the issues associated with incomplete occlusion and aneurysm recurrence.…”

Section: Introductionmentioning

confidence: 99%

Effects of Carbon Nanotube Infiltration on a Shape Memory Polymer‐Based Device for Brain Aneurysm Therapeutics: Design and Characterization of a Joule‐Heating Triggering Mechanism

et al. 2021

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Current endovascular therapies for intracranial aneurysms face limitations that include aneurysm recurrence and incomplete occlusion. These challenges can potentially be addressed by occluding the aneurysm space with shape memory polymers (SMPs) that are tailorable to patient‐specific aneurysm geometries to improve the suboptimal treatment outcomes associated with coil embolization. However, deployment of the SMP‐based device into the aneurysm requires external stimuli to trigger shape recovery. Thus, herein, the infiltration of carbon nanotubes (CNTs) in a polyurethane SMP foam is investigated, and Joule‐heating triggering for SMP shape recovery in endovascular therapy applications is demonstrated. The results show that CNTs can be successfully infiltrated in the SMP foam, providing tunable resistivity and shape recovery time, and that CNT infiltration reduces the glass transition temperature of the SMP and alters its mechanical properties, which is evidenced with a cumulative stress reduction in cyclic compression tests. Finally, the Joule‐heating capability of the SMP material is examined using a proof‐of‐concept in vitro occlusion experiment of an idealized saccular aneurysm model. Collectively, this study indicates that CNT infiltration of SMP foams is a promising approach in the design of electrically triggered embolic devices for individualized treatment of intracranial aneurysms.

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“…[ 31 ] Most importantly,

T_{normalg}

Section: Introductionmentioning

confidence: 99%

Effects of Carbon Nanotube Infiltration on a Shape Memory Polymer‐Based Device for Brain Aneurysm Therapeutics: Design and Characterization of a Joule‐Heating Triggering Mechanism

et al. 2021

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“…Two approaches are mainly taken, either the viscoelastic approach or the phase transition approach [ 43 ], to analyze and model the behavior of SMPs. Significant progress has been made in optimizing and broadening the transforming behaviors of shape-memory polymers to not limit them with bare dual shape-memory transitions [ 44 , 45 ].…”

Section: Classifications and Underlying Mechanisms Of Intelligent Polymersmentioning

confidence: 99%

Intelligent Polymers, Fibers and Applications

Reddy

Jayathilaka

et al. 2021

Polymers

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Intelligent materials, also known as smart materials, are capable of reacting to various external stimuli or environmental changes by rearranging their structure at a molecular level and adapting functionality accordingly. The initial concept of the intelligence of a material originated from the natural biological system, following the sensing–reacting–learning mechanism. The dynamic and adaptive nature, along with the immediate responsiveness, of the polymer- and fiber-based smart materials have increased their global demand in both academia and industry. In this manuscript, the most recent progress in smart materials with various features is reviewed with a focus on their applications in diverse fields. Moreover, their performance and working mechanisms, based on different physical, chemical and biological stimuli, such as temperature, electric and magnetic field, deformation, pH and enzymes, are summarized. Finally, the study is concluded by highlighting the existing challenges and future opportunities in the field of intelligent materials.

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“…For more accurate modelling, the dependence of volume fraction on pressure and temperature should also be considered. In addition, the VUMAT subroutine presented can be developed for other filler types used in SMP foam structures [58]. One of the most applicable fillers is carbon nanotubes.…”

Section: Experiments (T=20°c Sr=30%/min)mentioning

confidence: 99%

Nonlinear Finite Element Modelling of Thermo-Visco-Plastic Styrene and Polyurethane Shape Memory Polymer Foams

et al. 2021

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This paper presents nonlinear finite element (FE) models to predict time- and temperature-dependent responses of shape memory polymer (SMP) foams in the large deformation regime. For the first time, an A SMP foam constitutive model is implemented in the ABAQUS FE package with the aid of a VUMAT subroutine to predict thermo-visco-plastic behaviors. A phenomenological constitutive model is reformulated adopting a multiplicative decomposition of the deformation gradient into thermal and mechanical parts considering visco-plastic SMP matrix and glass microsphere inclusions. The stress split scheme is considered by a Maxwell element in parallel with a hyper-elastic rubbery spring. The Eyring dashpot is used for modelling the isotropic resistance to the local molecular rearrangement such as chain rotation. A viscous flow rule is adopted to prescribe shear viscosity and stress. An evolution rule is also considered for the athermal shear strengths to simulate macroscopic post-yield strain-softening behavior. In order to validate the accuracy of the model as well as the solution procedure, the numerical results are compared to experimental responses of Styrene and Polyurethane SMP foams at different temperatures and under different strain rates. The results show that the introduced FE modelling procedure is capable of capturing the major phenomena observed in experiments such as elastic and elastic-plastic behaviors, softening plateau regime, and densification.

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Nano/microstructures of shape memory polymers: from materials to applications

Abstract: This review summarizes the advances and challenges of shape memory polymers with nano/microstructures from materials to applications.

Cited by 74 publications

References 164 publications

Effects of Carbon Nanotube Infiltration on a Shape Memory Polymer‐Based Device for Brain Aneurysm Therapeutics: Design and Characterization of a Joule‐Heating Triggering Mechanism

Effects of Carbon Nanotube Infiltration on a Shape Memory Polymer‐Based Device for Brain Aneurysm Therapeutics: Design and Characterization of a Joule‐Heating Triggering Mechanism

Intelligent Polymers, Fibers and Applications

Nonlinear Finite Element Modelling of Thermo-Visco-Plastic Styrene and Polyurethane Shape Memory Polymer Foams

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