Dissipative particle dynamics simulation of microphase separation in polyurethane urea nanocomposites

Shape‐memory polymers (SMPs) induced by heat or water are commonly used candidates for biomedical applications. Shape recovery inevitably leads to a dramatic decrease of Young's modulus due to the enhanced flexibility of polymer chains at the transition temperature. Herein, the principle of phase‐transition‐induced stiffening of shape‐memory metallic alloys (SMAs) is introduced to the design of molecular structures for shape‐memory polyurethane (SMPUs), featuring all‐hard segments composed of main chains that are attached with poly(ethylene glycol) (PEG) dangling side chains. Different from conventional SMPs, they achieve a soft‐to‐stiff transition when shape recovers. The stiffening process is driven by water‐triggered segmental rearrangement due to the incompatibility between the hard segments and the soft PEG segments. Upon hydration, the extent of microphase separation is enhanced and the hard domains are transformed to a more continuous morphology to realize more effective stress transfer. Meanwhile, such segmental rearrangement facilitates the shape‐recovery process in the hydrated state despite the final increased glass transition temperature (Tg). This work represents a novel paradigm of simultaneously integrating balanced mechanics, shape‐memory property, and biocompatibility for SMPUs as materials for minimally invasive surgery such as endoluminal stents.

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“…The RDF curve corroborates the DMA and SAXS results and indicates more segregated hard and soft phases in SPPU4W. [ 25b,26 ]…”

Section: Resultssupporting

confidence: 77%

Water‐Triggered Stiffening of Shape‐Memory Polyurethanes Composed of Hard Backbone Dangling PEG Soft Segments

et al. 2022

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“…In addition, according to radial distribution functions (RDF) curves, that was, the probability that the same beads within the certain distance range, the aggregation degree of PEG beads on the surface might be objectively inferred. 30 , 31 Within the same distance range, the peak of aggregation of PEG beads in PCL 20 -MPEG micelle ( Figure 4 . D) appeared the earliest and was the highest (1.0).…”

Section: Resultsmentioning

confidence: 92%

Poly(ϵ-Caprolactone)-Methoxypolyethylene Glycol (PCL-MPEG)-Based Micelles for Drug-Delivery: The Effect of PCL Chain Length on Blood Components, Phagocytosis, and Biodistribution

Hou¹,

Zhou²,

Guo³

et al. 2022

IJN

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Background The main challenge of polymeric micelles as drug delivery systems is that the actual delivery efficiency is not as high as expected, which is closely related with the interactions with the complex biological environments such as blood components, phagocytosis, and biodistribution. Herein, we expect to understand these concerns for the clinically relevant micelles that composed of methoxypolyethylene glycol (MPEG) with identical chain length And poly(ε-caprolactone) (PCL) with tunable chain length (PCL n -MPEG) (n=20, 30, and 40) wherein doxorubicin was encapsulated as a model drug. Methods The doxorubicin-loaded PCL n -MPEG micelles were prepared by a dialysis method and characterized by dynamic light scattering and transmission electron microscopy. The surface PEG density and chain conformation were investigated by dissipative particle dynamics simulation. The stability of the micelles was detected by nanoparticle tracking analysis. The effects of PCL chain length on the blood components, phagocytosis, and biodistribution were assayed in vitro and in vivo. Results The micelles exhibited spherical morphology with a diameter about 30nm. The PEG chain conformation from “mushroom-like” to “brush-like” was evident. The micelles have no remarkable effect on the red blood cells, blood coagulation, and platelet activation. Interestingly, the protein adsorption was affected and dependent on the chain conformation, with lowest adsorption for PCL 30 -MPEG, which also has the loWest phagocytosis. The stability of the micelles was in the order of PCL 40 -MPEG>PCL 30 -MPEG>PCL 20 -MPEG which was dependent on the PCL chain length. The micelles mainly accumulated in liver, with the order consistent with their stability, indicating that, besides the phagocytosis, the stability of the micelle plays an important role in biodistribution as well. The related mechanisms were proposed and discussed. Conclusion Manipulating the PEG/PCL ratio of the micelle is an effective approach to modulate the protein adsorption, phagocytosis, and biodistribution, which may be a prerequisite for clinical applications.

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“…Polyurethanes (PUs) are block copolymers composed of soft and hard segments 1 . The soft segments are polyether or polyester based polyols, while the hard segments are isocyanates attached to the chain extenders 2,3 .…”

Section: Introductionmentioning

confidence: 99%

A review on electrically conductive polyurethane nanocomposites: From principle to application

Jafarzadeh,

Farzaneh,

Haddadi‐Asl

et al. 2023

Polymer Composites

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Polyurethanes (PUs) thanks to the occurrence of phase separation and biphasic structure prevail over other polymer matrixes for impregnation of conductive fillers and production of conductive composites. A number of carbonous fillers including carbon black, carbon fiber, carbon nanotube, graphite and its derivatives, and fullerene can be loaded into the PU matrixes to impart electrical conductivity. The properties of the carbonous fillers, the filler/PU interactions, and the method of compositing determine the conductive performance of the composite. It is possible to modulate the properties of the conductive PU composites and employ them for a number of electronic applications including but not limited to the strain sensors, electromagnetic interference shielding materials, supercapacitors, and tissue engineering scaffolds. In the present review, first, the distinctive properties of PU as a matrix of conductive composites have been discussed. Then, various carbon fillers loaded into the PU matrixes and their structural and conductive properties have been debated. Thereafter, the fabrication methods of the conductive composites as well as the influential parameters on the electrical properties of the composites have been reviewed to provide an insight into how fulfill a PU composite with the desired electrical performance. And finally, a number of applications of conductive PU composites have been put forward.Highlights Polyurethanes are very capable matrixes for conductive composites. Carbonous fillers can be loaded into the PU matrixes to impart conductivity. Conductive PU composites are employed for a number of electronic applications. Herein, properties, fillers, and applications of PU composites are reviewed.

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Dissipative particle dynamics simulation of microphase separation in polyurethane urea nanocomposites

Cited by 12 publications

References 20 publications

Water‐Triggered Stiffening of Shape‐Memory Polyurethanes Composed of Hard Backbone Dangling PEG Soft Segments

Water‐Triggered Stiffening of Shape‐Memory Polyurethanes Composed of Hard Backbone Dangling PEG Soft Segments

Poly(ϵ-Caprolactone)-Methoxypolyethylene Glycol (PCL-MPEG)-Based Micelles for Drug-Delivery: The Effect of PCL Chain Length on Blood Components, Phagocytosis, and Biodistribution

A review on electrically conductive polyurethane nanocomposites: From principle to application

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