Photothermal properties of shape memory polymer micro‐actuators for treating stroke*

Maitland, Duncan J.; Metzger, Melodie F.; Schumann, Daniel L; Lee, Abraham P.; Wilson, Thomas S.

doi:10.1002/lsm.10007

Cited by 301 publications

(202 citation statements)

References 14 publications

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“…Thermo-responsive SMP-based mechanical clot extraction devices to treat ischemic stroke was reported by Maitland et al [39]. Their fabricated catheter is photothermally activated, so it can easily remove the clot and finally relieve of the ischemia.…”

Section: Biomedical Applications Of Smpumentioning

confidence: 99%

Polyurethane: A Shape Memory Polymer (SMP)

Thakur¹,

Hu²

2017

Aspects of Polyurethanes

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Shape memory polymer (SMP) is a stimuli-responsive material with the ability to alter a programmed shape to its original shape upon triggering of an appropriate stimulus. For the past decades, SMP has dragged much interest in material field owing to its various and versatile applications. One archetypal SMP is polyurethane, which has a wideranging transition temperature for its shape recovery, retraction temperatures, inherent soft-hard segments, a high recoverable strain (up to 400%), high control of the softening, favorable and tunable physical properties, and so on. This chapter emphasizes on the raw materials required for the synthesis of shape memory polyurethane (SMPU), the principle of shape memory function, the design of protocol of SMPU, and their applications with future directions.

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Section: Biomedical Applications Of Smpumentioning

confidence: 99%

Polyurethane: A Shape Memory Polymer (SMP)

Thakur¹,

Hu²

2017

Aspects of Polyurethanes

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“…Such rudimentary early applications did not necessitate a detailed understanding or modeling of the thermomechanical behavior of these materials. However, in recent years shape-memory polymers are beginning to be used for critical biomedical applications (e.g., Lendlein and Langer, 2002;Metcalfe et al, 2003;Baer et al, 2007b), microsystems (e.g., Maitland et al, 2002;Metzger et al, 2002;Gall et al, 2004), re-writable media for data storage (e.g., Vettiger et al, 2002;Wornyo et al, 2007), and self-deployable space structures (Campbell et al, 2005). In order to develop a robust simulationbased capability for the design of devices for such critical applications, one requires an underlying accurate thermo-mechanically-coupled constitutive theory and an attendant validated numerical implementation of the theory.…”

Section: Introductionmentioning

confidence: 99%

Thermally actuated shape-memory polymers: Experiments, theory, and numerical simulations

Srivastava

Chester

Anand

2010

Journal of the Mechanics and Physics of Solids

165

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With the aim of developing a thermo-mechanically-coupled large-deformation constitutive theory and a numerical-simulation capability for modeling the response of thermally-actuated shape-memory polymers, we have (i) conducted large strain compression experiments on a representative shape-memory polymer to strains of approximately unity at strain rates of 10 −3 s −1 and 10 −1 s −1 , and at temperatures ranging from room temperature to approximately 30 C above the glass transition temperature of the polymer; (ii) formulated a thermo-mechanically-coupled large-deformation constitutive theory; (iii) calibrated the material parameters appearing in the theory using the stress-strain data from the compression experiments; (iv) numerically implemented the theory by writing a user-material subroutine for a widely-used finite element program; and (v) conducted representative experiments to validate the predictive capability of our theory and its numerical implementation in complex three-dimensional geometries. By comparing the numericallypredicted response in these validation simulations against measurements from corresponding experiments, we show that our theory is capable of reasonably accurately reproducing the experimental results. As a demonstration of the robustness of the three-dimensional numerical capability, we also show results from a simulation of the shape-recovery response of a stent made from the polymer when it is inserted in an artery modeled as a compliant elastomeric tube.

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“…If polymers cannot be warmed up by heat transfer using a hot liquid or gaseous medium, noncontact triggering will be required. Light-activation has been realized by heating thermally induced shape-memory polymers by irradiation (10,16,17). In addition, light-induced shape-memory polymers (18) have recently been developed, which use photosensitive functional groups as molecular switches.…”

mentioning

confidence: 99%

Initiation of shape-memory effect by inductive heating of magnetic nanoparticles in thermoplastic polymers

Mohr

Kratz

Weigel

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

756

586

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In shape-memory polymers, changes in shape are mostly induced by heating, and exceeding a specific switching temperature, T switch. If polymers cannot be warmed up by heat transfer using a hot liquid or gaseous medium, noncontact triggering will be required. In this article, the magnetically induced shape-memory effect of composites from magnetic nanoparticles and thermoplastic shapememory polymers is introduced. A polyetherurethane (TFX) and a biodegradable multiblock copolymer (PDC) with poly(p-dioxanone) as hard segment and poly( -caprolactone) as soft segment were investigated as matrix component. Nanoparticles consisting of an iron(III)oxide core in a silica matrix could be processed into both polymers. A homogeneous particle distribution in TFX could be shown. Compounds have suitable elastic and thermal properties for the shape-memory functionalization. Temporary shapes of TFX compounds were obtained by elongating at increased temperature and subsequent cooling under constant stress. Cold-drawing of PDC compounds at 25°C resulted in temporary fixation of the mechanical deformation by 50 -60%. The shape-memory effect of both composite systems could be induced by inductive heating in an alternating magnetic field (f ‫؍‬ 258 kHz; H ‫؍‬ 30 kA⅐m ؊1 ). The maximum temperatures achievable by inductive heating in a specific magnetic field depend on sample geometry and nanoparticle content. Shape recovery rates of composites resulting from magnetic triggering are comparable to those obtained by increasing the environmental temperature.nanocomposite ͉ shape-memory polymer ͉ stimuli-sensitive polymer S hape-memory polymers are able to recover their predefined original shape when exposed to an external stimulus. A prerequisite for the shape-memory effect is a preceding functionalization of the material to temporarily fix a mechanical deformation. Most shape-memory polymers are thermosensitive materials. The shape is actuated by exceeding a specific switching temperature, T switch (1). Thermoplastic shape-memory polymers have at least two separated phases, where the domains with the highest thermal transition (T perm ) stabilize the permanent shape by acting as physical netpoints. A second phase having another thermal transition T trans serves as switch. At temperatures above T trans the chain segments forming this phase are flexible and the material is highly elastic, whereas the flexibility of the chains below T trans is limited and enables the fixation of the temporary shape. T trans can either be a glass transition (T g ) or a melting temperature (T m ). Whereas T trans is the thermal transition of the switching segment phase, typically determined by differential scanning calorimetry (DSC), T switch is result of a thermomechanical test used to quantify the shape-memory effect.An important class of thermoplastic shape-memory polymers are polyurethanes. They often contain a hard segment from methylene bis(4-phenylisocyanate) (MDI) and 1,4-butanediol. Depending on the switching segment, T trans can be either a melting...

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Photothermal properties of shape memory polymer micro‐actuators for treating stroke*

Abstract: Laser-activated SMP devices are a unique combination of laser-tissue and biomaterial technologies. Successful deployment of the microactuator requires well-engineered coupling of the light from the diffusing fiber through the blood into the SMP.

Cited by 301 publications

References 14 publications

Polyurethane: A Shape Memory Polymer (SMP)

Polyurethane: A Shape Memory Polymer (SMP)

Thermally actuated shape-memory polymers: Experiments, theory, and numerical simulations

Initiation of shape-memory effect by inductive heating of magnetic nanoparticles in thermoplastic polymers

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