scholarly journals Light-triggered topological programmability in a dynamic covalent polymer network

2020 ◽  
Vol 6 (13) ◽  
pp. eaaz2362 ◽  
Author(s):  
Weike Zou ◽  
Binjie Jin ◽  
Yi Wu ◽  
Huijie Song ◽  
Yingwu Luo ◽  
...  
Keyword(s):  
Network Topology ◽  
Material Properties ◽  
Polymer Network ◽  
Polymer Networks ◽  
Isomerization Reaction ◽  
Network Polymer ◽  
Robotic Arms ◽  
Practical Applications ◽  
Topological States ◽  
High Degree

Dynamic covalent polymer networks exhibit unusual adaptability while maintaining the robustness of conventional covalent networks. Typically, their network topology is statistically nonchangeable, and their material properties are therefore nonprogrammable. By introducing topological heterogeneity, we demonstrate a concept of topology isomerizable network (TIN) that can be programmed into many topological states. Using a photo-latent catalyst that controls the isomerization reaction, spatiotemporal manipulation of the topology is realized. The overall result is that the network polymer can be programmed into numerous polymers with distinctive and spatially definable (thermo-) mechanical properties. Among many opportunities for practical applications, the unique attributes of TIN can be explored for use as shape-shifting structures, adaptive robotic arms, and fracture-resistant stretchable devices, showing a high degree of design versatility. The TIN concept enriches the design of polymers, with potential expansion into other materials with variations in dynamic covalent chemistries, isomerizable topologies, and programmable macroscopic properties.

scholarly journals Influence of Material Properties on the Damage-Reporting and Self-Healing Performance of a Mechanically Active Dynamic Network Polymer in Coating Applications

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2468
Author(s):  
Da Hae Son ◽  
Gi Young Kim ◽  
Ji-Eun Jeong ◽  
Sang-Ho Lee ◽  
Young Il Park ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Material Properties ◽  
Substrate Surface ◽  
Polymer Network ◽  
Polymer Networks ◽  
Indentation Hardness ◽  
Indentation Modulus ◽  
Self Healing

We conducted a detailed investigation of the influence of the material properties of dynamic polymer network coatings on their self-healing and damage-reporting performance. A series of reversible polyacrylate urethane networks containing the damage-reporting diarylbibenzofuranone unit were synthesized, and their material properties (e.g., indentation modulus, hardness modulus, and glass-transition temperature) were measured conducting nanoindentation and differential scanning calorimetry experiments. The damage-reporting and self-healing performances of the dynamic polymer network coatings exhibited opposite tendencies with respect to the material properties of the polymer network coatings. Soft polymer network coatings with low glass-transition temperature (~10 °C) and indentation hardness (20 MPa) exhibited better self-healing performance (almost 100%) but two times worse damage-reporting properties than hard polymer network coatings with high glass-transition temperature (35~50 °C) and indentation hardness (150~200 MPa). These features of the dynamic polymer network coatings are unique; they are not observed in elastomers, films, and hydrogels, whereby the polymer networks are bound to the substrate surface. Evidence indicates that controlling the polymer’s physical properties is a key factor in designing high-performance self-healing and damage-reporting polymer coatings based on mechanophores.

scholarly journals Thermoset Polymer Matrix Structure and Properties: Coarse-Grained Simulations

Polymers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 36 ◽  
Author(s):  
Vladimir Rudyak ◽  
Elizaveta Efimova ◽  
Daria Guseva ◽  
Alexander Chertovich
Keyword(s):  
Network Topology ◽  
Dissipative Particle Dynamics ◽  
Polymer Network ◽  
Polymer Networks ◽  
Covalent Bond ◽  
Mesh Size ◽  
Coarse Grained ◽  
Topological Parameters ◽  
Thermoset Polymer ◽  
Plasticizer Concentration

The formation of a thermoset polymer network is a complex process with great variability. In this study, we used dissipative particle dynamics and graph theory tools to investigate the curing process and network topology of a phthalonitrile thermoset to reveal the influence of initiator and plasticizer concentration on its properties. We also propose a novel way to characterize the network topology on the basis of two independent characteristics: simple cycle length (which is mainly affected by the initiator amount) and the number of simple cycles passing through a single covalent bond (which is determined primarily by plasticizer concentration). These values can be treated in the more familiar terms of network “mesh size” and “sponginess”, correspondingly. The combination of these two topological parameters allows one to characterize any given network in an implicit but precise way and predict the resulting network properties, including the mechanical modulus. We believe that the same approach could be useful for other polymer networks as well, including rubbers and gels.

scholarly journals DNA Aptamer Functionalized Hydrogels for Interferometric Fiber-Optic Based Continuous Monitoring of Potassium Ions

Biosensors ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 266
Author(s):  
Nataša Žuržul ◽  
Bjørn Torger Stokke
Keyword(s):  
Conformational Transition ◽  
Polymer Network ◽  
Potassium Ion ◽  
Ion Concentration ◽  
Dna Aptamer ◽  
Blood Levels ◽  
Label Free ◽  
Practical Applications ◽  
Hydrogel Matrix ◽  
K Concentration

In the present paper, we describe a potassium sensor based on DNA-aptamer functionalized hydrogel, that is capable of continuous label-free potassium ion (K+) monitoring with potential for in situ application. A hydrogel attached to the end of an optical fiber is designed with di-oligonucleotides grafted to the polymer network that may serve as network junctions in addition to the covalent crosslinks. Specific affinity toward K+ is based on exploiting a particular aptamer that exhibits conformational transition from single-stranded DNA to G-quadruplex formed by the di-oligonucleotide in the presence of K+. Integration of this aptamer into the hydrogel transforms the K+ specific conformational transition to a K+ concentration dependent deswelling of the hydrogel. High-resolution interferometry monitors changes in extent of swelling at 1 Hz and 2 nm resolution for the hydrogel matrix of 50 µm. The developed hydrogel-based biosensor displayed high selectivity for K+ ions in the concentration range up to 10 mM, in the presence of physiological concentrations of Na+. Additionally, the concentration dependent and selective K+ detection demonstrated in the artificial blood buffer environment, both at room and physiological temperatures, suggests substantial potential for practical applications such as monitoring of potassium ion concentration in blood levels in intensive care medicine.

scholarly journals Broadband metamaterials and metasurfaces: a review from the perspectives of materials and devices

Nanophotonics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 3165-3196 ◽  
Author(s):  
Joonkyo Jung ◽  
Hyeonjin Park ◽  
Junhyung Park ◽  
Taeyong Chang ◽  
Jonghwa Shin
Keyword(s):  
Material Properties ◽  
Frequency Bandwidth ◽  
Broad Bandwidth ◽  
Practical Applications ◽  
Effective Material Properties

AbstractMetamaterials can possess extraordinary properties not readily available in nature. While most of the early metamaterials had narrow frequency bandwidth of operation, many recent works have focused on how to implement exotic properties and functions over broad bandwidth for practical applications. Here, we provide two definitions of broadband operation in terms of effective material properties and device functionality, suitable for describing materials and devices, respectively, and overview existing broadband metamaterial designs in such two categories. Broadband metamaterials with nearly constant effective material properties are discussed in the materials part, and broadband absorbers, lens, and hologram devices based on metamaterials and metasurfaces are discussed in the devices part.

scholarly journals Measurement and Process Control in Precision Hot Embossing

2013 ◽  
Author(s):  
Maia R. Bageant ◽  
David E. Hardt
Keyword(s):  
Process Control ◽  
Material Properties ◽  
Disturbance Rejection ◽  
Closed Loop ◽  
Hot Embossing ◽  
Commercial Production ◽  
Bulk Deformation ◽  
Functional Tests ◽  
Medical Field ◽  
High Degree

Microfluidic technologies hold a great deal of promise in advancing the medical field, but transitioning them from research to commercial production has proven problematic. We propose precision hot embossing as a process to produce high volumes of devices with low capital cost and a high degree of flexibility. Hot embossing has not been widely applied to precision forming of hard polymers at viable production rates. To this end we have developed experimental equipment capable of maintaining the necessary precision in forming parameters while minimizing cycle time. In addition, since equipment precision alone does not guarantee consistent product quality, our work also focuses on real-time sensing and diagnosis of the process. This paper covers both the basic details for a novel embossing machine, and the utilization of the force and displacement data acquired during the embossing cycle to diagnose the state of the material and process. The precision necessary in both the forming machine and the instrumentation will be covered in detail. It will be shown that variation in the material properties (e.g. thickness, glass transition temperature) as well as the degree of bulk deformation of the substrate can be detected from these measurements. If these data are correlated with subsequent downstream functional tests, a total measure of quality may be determined and used to apply closed-loop cycle-to-cycle control to the entire process. By incorporating automation and specialized precision equipment into a tabletop “microfactory” setting, we aim to demonstrate a high degree of process control and disturbance rejection for the process of hot embossing as applied at the micron scale.

A New Derivation of Postgel Properties of Network Polymers

1976 ◽  
Vol 49 (5) ◽  
pp. 1219-1231 ◽  
Author(s):  
D. R. Miller ◽  
C. W. Macosko
Keyword(s):  
General Result ◽  
Crosslink Density ◽  
Polymer Network ◽  
Probability Generating Function ◽  
Finite Chain ◽  
Network Polymer ◽  
Network Polymers ◽  
Property Relations ◽  
Recursive Scheme ◽  
Effective Network

Abstract The probability of a finite or dangling chain on an ideal polymer network has been derived by a simple recursive scheme. In contrast to the method of Dobson and Gordon, probability generating function formalism is not required. The general result, Equations (21), and its specific solutions, Equations (23), (24), and (30), give the finite chain probability as a function of reactant type and extent of polymerization. They cover most of the important types of network forming polymerizations. From the finite chain probability, useful property relations such as sol fraction, crosslink density, and the number of elastically effective network chains are developed. Because of their simplicity, we expect these relations to be further developed and applied to network polymer property measurements.

Direct characterization of a polymer network through its retainable units

2019 ◽  
Vol 10 (35) ◽  
pp. 4837-4843
Author(s):  
Xiaoyan Xu ◽  
Qi Wang
Keyword(s):  
Polymer Network ◽  
Polymer Networks ◽  
Quantitative Characterization

A partially decrosslinkable network provides a general protocol for full, direct and quantitative characterization of polymer networks through its retainable units.

scholarly journals Study of the physicochemical properties of exosome dispersions obtained by ultrafiltration

2019 ◽  
Vol 135 ◽  
pp. 01096 ◽  
Author(s):  
Elena Kastarnova ◽  
Vladimir Orobets ◽  
Valeria Shakhova ◽  
Olga Sevostyanova ◽  
Natalya Kizilova
Keyword(s):  
Physicochemical Properties ◽  
Material Properties ◽  
Membrane Vesicles ◽  
Filter Material ◽  
Delivery Vehicle ◽  
Flow Cytometry Data ◽  
Preparation Stage ◽  
High Degree ◽  
Main Impurity

The article presents the results of studying the physicochemical properties of exosome preparations obtained by ultrafiltration, which indicate a high degree of the composition and properties dependence of the obtained product on the material of the filters used. Quantitative determination of proteins and nucleic acids in exosome samples using UPN-50 filters allows us to conclude that the content of the main impurity compounds in the preparation is significantly reduced compared to dispersions obtained using filters with pore sizes of 220 and 450 nm. Analysis of flow cytometry data made it possible to demonstrate that when using the UPN-50 filter, an increase in the contribution to the dispersion of all types of fractions of non-exosomal size was observed, the appearance of which can result from fraction destruction associated with pore size or filter material properties. drying of the dispersion was observed in the studied exosome samples. Fraction sizes ranged from 40 to 450 nm (an average of about 200 nm). Exosomes from the entire variety of membrane vesicles are fractions that have the most suitable characteristics that allow them to be used as a nanoscale drug delivery vehicle while ensuring the necessary quality control of the drug at the sample preparation stage.

The Design Tradeoffs of Linear Functionally Graded Piezoceramic Actuators

Aerospace ◽  
2003 ◽  
Author(s):  
Paul W. Alexander ◽  
Diann Brei
Keyword(s):  
Material Properties ◽  
High Stress ◽  
Functionally Graded ◽  
Homogeneous Material ◽  
Stress Concentrations ◽  
Practical Applications ◽  
Complex Electric Field ◽  
Design Tradeoffs ◽  
A Minor ◽  
The Cost

It is common practice to reduce the voltage level within piezoelectric actuators by utilizing multiple layers, typically bonded together. Unfortunately, this has a tendency to result in device failure due to delamination. For example, with benders the typical lifetime is 105 to 106 cycles, limiting its use in practical applications. This poses an interesting design tradeoff: the stroke is increased due to sharper gradients between material layers; however, the higher gradients lead to high stress concentrations at those interfaces. One approach to reducing these stresses is to grade the material properties through a monolithic piece of piezoceramic so that no interfaces or bonding elements exist, but this comes at the cost of stroke. This paper explores the design tradeoff inherent to monolithic functionally graded piezoelectrics. An analytical free-displacement model for a monolithic piezoceramic beam with a generic gradient is derived. Key to this is the inclusion of the complex electric field distribution which rises from the non-homogeneous material properties. This model is used along with finite element models to examine the effect of continuous linear and stepwise material gradients on the displacement performance as well as the stress levels. The study shows that using monolithic functionally graded piezocermics can significantly reduce the stresses with only a minor impact on the device stroke.

scholarly journals Polymer network-derived nitrogen/sulphur co-doped three-dimensionally interconnected hierarchically porous carbon for oxygen reduction, lithium-ion battery, and supercapacitor

RSC Advances ◽  
2019 ◽  
Vol 9 (63) ◽  
pp. 36570-36577 ◽  
Author(s):  
Zili Xu ◽  
Fangfang Zhang ◽  
Weiran Lin ◽  
Haining Zhang
Keyword(s):  
Porous Carbon ◽  
Large Scale ◽  
Polymer Network ◽  
Polymer Networks ◽  
Lithium Ion ◽  
Scale Production ◽  
Hierarchical Porous Carbon ◽  
Large Scale Production ◽  
Hierarchical Porous ◽  
Co Doped

Polymer networks are efficient precursors for large scale production of hierarchical porous carbon.

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