A Transient Microsphere Model for Nonlinear Viscoelasticity in Dynamic Polymer Networks

2021 ◽  
Vol 89 (1) ◽  
Author(s):  
Samuel Lamont ◽  
Franck J. Vernerey
Keyword(s):  
Nonlinear Viscoelasticity ◽  
Polymer Networks ◽  
Planck Equation ◽  
Network Evolution ◽  
Material Behavior ◽  
Published Data ◽  
Directional Statistics ◽  
Polymer Systems ◽  
Chain Level ◽  
Microsphere Model

Abstract Viscoelastic material behavior in polymer systems largely arises from dynamic topological rearrangement at the network level. In this paper, we present a physically motivated microsphere formulation for modeling the mechanics of transient polymer networks. By following the directional statistics of chain alignment and local chain stretch, the transient microsphere model (TMM) is fully anisotropic and micro-mechanically based. Network evolution is tracked throughout deformation using a Fokker–Planck equation that incorporates the effects of bond creation and deletion at rates that are sensitive to the chain-level environment. Using published data, we demonstrate the model to capture various material responses observed in physical polymers.

Development of New Polymer Systems and Quantum Dots - Polymer Nanocomposites for Low-cost, Flexible OLED Display Applications

2011 ◽  
Vol 1359 ◽  
Author(s):  
Lihua Zhao ◽  
Zhang-Lin Zhou ◽  
Zengshan Guo ◽  
Jian Pei ◽  
Samuel Mao
Keyword(s):  
Quantum Dots ◽  
Polymer Nanocomposites ◽  
Photophysical Properties ◽  
Polymer Network ◽  
Polymer Networks ◽  
Life Time ◽  
Hole Transport ◽  
Interpenetrating Polymer Networks ◽  
Solution Processing ◽  
Polymer Systems

ABSTRACTRecently, tremendous progress has been made toward application of organic (small molecule/polymer) light-emitting diodes (OLEDs) in full color flat panel displays and other devices. However, with current technologies, OLEDs are still struggling with high manufacturing costs which really limit the size of OLEDs panels and with life time, especially differential aging of colors. To be more cost-effective for fabricating OLEDs, we believe solution-processing would be an attractive path due to its simplicity and highly reduced equipment costs. This proceeding paper discusses our recent progress in development of new polymer systems that are highly solvent-resistant but maintaining their photophysical properties and hybrid quantum-dots (QDs)-polymer nanocomposites for their use in multicolor and multilayer OLEDs pixels through solution-processing. Our new polymer systems are named conductive semi-interpenetrating polymer networks (C-Semi-IPNs) served in different layers of OLEDs devices, containing an inert polymer network and conducting polymer(s) including hole transport and emissive materials. Since these do not require complicated chemical modification or introduction of reactive moieties to OLED materials, many state-of-the-arts emissive polymers can be utilized to achieve RGB and white OLEDs. The research findings on hybrid QDoligomer nanocomposite as a good analogue lead to the successful design and synthesis of QDpolymer nanocomposites which were used to build proof-of-the-concept devices showing a good promise in providing excellent color purity and stability as well as device robustness.

Comparison of memory effects in multiblock copolymers and covalently crosslinked multiphase polymer networks composed of the same types of oligoester segments and urethane linker

2013 ◽  
Vol 1569 ◽  
pp. 123-128
Author(s):  
Li Wang ◽  
Ulrich Nöchel ◽  
Marc Behl ◽  
Karl Kratz ◽  
Andreas Lendlein
Keyword(s):  
Shape Recovery ◽  
Polymer Networks ◽  
Memory Effects ◽  
Hexamethylene Diisocyanate ◽  
Multiblock Copolymers ◽  
Polymer Systems ◽  
Degradable Polymer ◽  
Temperature Memory Effect ◽  
Switching Temperature ◽  
Shape Fixity

ABSTRACTPhase-segregated multiblock copolymers (MBC) as well as covalently crosslinked multiphase polymer networks, which are composed of crystallizable oligo(ε-caprolactone) (OCL) and oligo(ω-pentadecalactone) (OPDL) segments have been recently introduced as degradable polymer systems exhibiting various memory effects. Both types of copolyesterurethane networks can be synthesized via co-condensation of the respective hydroxytelechelic oligomers and 2,2(4),4-trimethyl-hexamethylene diisocyanate (TMDI) as aliphatic linker.In this work the dual-shape properties as well as the temperature-memory capability of thermoplastics and covalently crosslinked copolyesterurethanes containing OCL and OPDL domains are explored. Both copolyesterurethane networks exhibited excellent dual-shape properties with high shape fixity ratios Rf ≥ 93% and shape recovery ratios in the range of 92% to 100% determined in the 2nd and 3rd test cycle, whereby the dual-shape performance was substantially improved when covalent crosslinks are present in the copolymer.A pronounced temperature-memory effect was achieved for thermoplastic as well as crosslinked copolyesterurethanes. Hereby, the switching temperature Tsw could be adjusted via the variation of the applied deformation temperature Tdeform in the range from 32 °C to 53 °C for MBC and in the range from 29 °C to 78 °C for multiphase polymer networks.

Topological structure and mechanics of glassy polymer networks

Soft Matter ◽  
2017 ◽  
Vol 13 (45) ◽  
pp. 8392-8401 ◽  
Author(s):  
Robert M. Elder ◽  
Timothy W. Sirk
Keyword(s):  
Network Architecture ◽  
Topological Structure ◽  
Glassy Polymer ◽  
Polymer Networks ◽  
Molecular Simulations ◽  
Coarse Grained ◽  
Graph Theoretic ◽  
Chain Level

The influence of chain-level network architecture (i.e., topology) on mechanics was explored for unentangled polymer networks using a blend of coarse-grained molecular simulations and graph-theoretic concepts.

scholarly journals Recent Advances in Functional Polymers Containing Coumarin Chromophores

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 56
Author(s):  
Ines Cazin ◽  
Elisabeth Rossegger ◽  
Gema Guedes de la Cruz ◽  
Thomas Griesser ◽  
Sandra Schlögl
Keyword(s):  
Polymer Networks ◽  
Cycloaddition Reaction ◽  
Functional Polymers ◽  
Future Application ◽  
Comprehensive Overview ◽  
Polymer Systems ◽  
Recent Developments ◽  
Photochemical Properties ◽  
Application Fields ◽  
Macromolecular Architecture

Natural and synthetic coumarin derivatives have gained increased attention in the design of functional polymers and polymer networks due to their unique optical, biological, and photochemical properties. This review provides a comprehensive overview over recent developments in macromolecular architecture and mainly covers examples from the literature published from 2004 to 2020. Along with a discussion on coumarin and its photochemical properties, we focus on polymers containing coumarin as a nonreactive moiety as well as polymer systems exploiting the dimerization and/or reversible nature of the [2πs + 2πs] cycloaddition reaction. Coumarin moieties undergo a reversible [2πs + 2πs] cycloaddition reaction upon irradiation with specific wavelengths in the UV region, which is applied to impart intrinsic healability, shape-memory, and reversible properties into polymers. In addition, coumarin chromophores are able to dimerize under the exposure to direct sunlight, which is a promising route for the synthesis and cross-linking of polymer systems under “green” and environment-friendly conditions. Along with the chemistry and design of coumarin functional polymers, we highlight various future application fields of coumarin containing polymers involving tissue engineering, drug delivery systems, soft robotics, or 4D printing applications.

Dynamics of Entangled Polymers

2015 ◽  
Author(s):  
Ronald G. Larson ◽  
Zuowei Wang
Keyword(s):  
Large Deformations ◽  
Nonlinear Viscoelasticity ◽  
Polymer Dynamics ◽  
Tube Model ◽  
Concentration Effects ◽  
Polymer Systems ◽  
Entangled Polymers ◽  
Entangled Polymer ◽  
Future Work ◽  
Entangled Polymer Solutions

This article explores the dynamics of entangled polymers, with particular emphasis on how the unusual and often dramatic mechanical properties of concentrated polymer systems are determined by the physics of entanglements. It begins with an overview of the foundations of entangled polymer dynamics, organized around tubes and slip links used in modeling entanglements, the packing length and concentration effects, the results of computer simulations on entanglements, topological contacts, and the effects of large deformations. The focus is on the nature of ‘entanglement’, both from a bottom-up molecular view, and from a phenomenological one. The discussion then turns to the linear viscoelasticity of entangled polymer solutions and melts, along with nonlinear viscoelasticity. Models of polymer dynamics in the linear regime are also described, including the ‘standard tube model’. The article concludes with suggestions for future work.

The Use of Monte Carlo Simulations for the Interpretation of Light Scattering and Fluorescence Data on Self-Assembling Polymer Systems in Solutions

2008 ◽  
Vol 73 (3) ◽  
pp. 293-313
Author(s):  
Pavel Matějíček ◽  
Filip Uhlík ◽  
Zuzana Limpouchová ◽  
Karel Procházka
Keyword(s):  
Monte Carlo ◽  
Light Scattering ◽  
Monte Carlo Simulations ◽  
Simplified Model ◽  
Necessary Condition ◽  
Published Data ◽  
Basic Principles ◽  
Feature Article ◽  
Polymer Systems ◽  
Self Assembling

In this feature article, we demonstrate the usefulness of tailor-made computer simulations for the interpretation of experimental data. Two examples of studies on self-assembling copolymer systems (by light scattering and fluorescence spectroscopy) performed some time ago are reviewed. It is shown how some unexpected and confusing results could have been interpreted using of Monte Carlo simulations. In both cases, a short outline of the experimental study including the motivation and the most important results is given first. Then the results of simulations are described and discussed with respect to the questions generated by experimental work. In this paper, we included both unpublished and already published data. Thus, the interpretation of the behavior and general conclusions are formulated in a retrospective way. The paper shows that simulations based on a considerably simplified model can complete the mosaic of evidences necessary for a reasonable interpretation of experimental results and can help to understand basic principles of their behavior. The necessary condition is that the model, even though strongly simplified, has to show all essential qualitative features of the behavior.

scholarly journals A Phenomenological Model for Mechanically Mediated Growth, Remodeling, Damage, and Plasticity of Gel-Derived Tissue Engineered Blood Vessels

2009 ◽  
Vol 131 (10) ◽  
Author(s):  
Julia Raykin ◽  
Alexander I. Rachev ◽  
Rudolph L. Gleason
Keyword(s):  
Blood Vessels ◽  
Damage Mechanics ◽  
Time Course ◽  
Material Behavior ◽  
Published Data ◽  
Mechanical Stimuli ◽  
Volumetric Growth ◽  
Model Framework ◽  
Modeling Framework ◽  
Tissue Engineered Blood Vessels

Mechanical stimulation has been shown to dramatically improve mechanical and functional properties of gel-derived tissue engineered blood vessels (TEBVs). Adjusting factors such as cell source, type of extracellular matrix, cross-linking, magnitude, frequency, and time course of mechanical stimuli (among many other factors) make interpretation of experimental results challenging. Interpretation of data from such multifactor experiments requires modeling. We present a modeling framework and simulations for mechanically mediated growth, remodeling, plasticity, and damage of gel-derived TEBVs that merge ideas from classical plasticity, volumetric growth, and continuum damage mechanics. Our results are compared with published data and suggest that this model framework can predict the evolution of geometry and material behavior under common experimental loading scenarios.

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