scholarly journals Molecular structure of self-healing polyampholyte hydrogels analyzed from tensile behaviors

Soft Matter ◽  
2015 ◽  
Vol 11 (48) ◽  
pp. 9355-9366 ◽  
Author(s):  
Tao Lin Sun ◽  
Feng Luo ◽  
Takayuki Kurokawa ◽  
Sadia Nazneen Karobi ◽  
Tasuku Nakajima ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Self Healing

We established a method to reveal the molecular structure of self-healing, viscoelastic gels from their tensile behaviors.

scholarly journals Effect of Molecular Structure in the Chain Mobility of Dichalcogenide-Based Polymers with Self-Healing Capacity

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1960 ◽  
Author(s):  
Mikel Irigoyen ◽  
Jon M. Matxain ◽  
Fernando Ruipérez
Keyword(s):  
Molecular Structure ◽  
Exchange Reaction ◽  
Initial Guess ◽  
The Self ◽  
Self Healing ◽  
Chain Mobility ◽  
Reaction Barriers ◽  
Dynamics Simulations ◽  
Two Parameters ◽  
Simulation Parameters

Recently, it has been shown that the reaction mechanism in self-healing diphenyl dichalcogenide-based polymers involves the formation of sulfenyl and selenyl radicals. These radicals are able to attack a neighbouring dichalcogenide bond via a three-membered transition state, leading to the interchange of chalcogen atoms. Hence, the chain mobility is crucial for the exchange reaction to take place. In this work, molecular dynamics simulations have been performed in a set of disulfide- and diselenide-based materials to analyze the effect of the molecular structure in the chain mobility. First of all, a validation of the computational protocol has been carried out, and different simulation parameters like initial guess, length of the molecular chains, size of the simulation box and simulation time, have been evaluated. This protocol has been used to study the chain mobility and also the self-healing capacity, which depends on the probability to generate radicals ( ρ ), the barrier of the exchange reaction ( Δ G ) and the mobility of the chains ( ω ). The first two parameters have been obtained in previous quantum chemical calculations on the systems under study in this work. After analyzing the self-healing capacity, it is concluded that aromatic diselenides (PD-SeSe) are the best candidates among those studied to show self-healing, due to lower reaction barriers and larger ω values.

Toward strong self-healing polyisoprene elastomers with dynamic ionic crosslinks

Soft Matter ◽  
2020 ◽  
Vol 16 (14) ◽  
pp. 3384-3394 ◽  
Author(s):  
Yohei Miwa ◽  
Junosuke Kurachi ◽  
Yusuke Sugino ◽  
Taro Udagawa ◽  
Shoichi Kutsumizu
Keyword(s):  
Molecular Structure ◽  
Self Healing ◽  
Ionic Crosslinks

We demonstrate the principle in the optimization of the molecular structure for the polyisoprene elastomer with dynamic ionic crosslinks to tune the mechanical and autonomous self-healing properties.

Surface modified halloysite nanotube enhanced imine-based epoxy composites with high self-healing efficiency and excellent mechanical properties

2021 ◽  
Vol 12 (37) ◽  
pp. 5342-5356
Author(s):  
Hao Jiang ◽  
Meng Cheng ◽  
Caijiao Ai ◽  
Fanjie Meng ◽  
Yizeng Mou ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Mechanical Properties ◽  
The Self ◽  
Epoxy Composites ◽  
Cross Linking ◽  
Schematic Diagram ◽  
Self Healing ◽  
Halloysite Nanotube ◽  
Healing Efficiency ◽  
Surface Modified

(a) Schematic diagram of the self-healing mechanism. (b) Illustration of the cross-linking effect and the internal molecular structure.

scholarly journals In-depth characterization of self-healing polymers based on π–π nteractions

2021 ◽  
Vol 17 ◽  
pp. 2496-2504
Author(s):  
Josefine Meurer ◽  
Julian Hniopek ◽  
Johannes Ahner ◽  
Michael Schmitt ◽  
Jürgen Popp ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Mechanical Damage ◽  
Analytical Techniques ◽  
The Self ◽  
Supramolecular Interactions ◽  
Supramolecular Polymers ◽  
Self Healing ◽  
Noncovalent Bonds ◽  
Tetracarboxylic Dianhydride

The self-healing behavior of two supramolecular polymers based on π–π-interactions featuring different polymer backbones is presented. For this purpose, these polymers were synthesized utilizing a polycondensation of a perylene tetracarboxylic dianhydride with polyether-based diamines and the resulting materials were investigated using various analytical techniques. Thus, the molecular structure of the polymers could be correlated with the ability for self-healing. Moreover, the mechanical behavior was studied using rheology. The activation of the supramolecular interactions results in a breaking of these noncovalent bonds, which was investigated using IR spectroscopy, leading to a sufficient increase in mobility and, finally, a healing of the mechanical damage. This scratch-healing behavior was also quantified in detail using an indenter.

Molecular Structure of the Outermost Cell Wall Component of Spirillum Serpens

1977 ◽  
Vol 35 ◽  
pp. 342-343
Author(s):  
Wah Chiu ◽  
David Grano
Keyword(s):  
Molecular Structure ◽  
Cell Wall ◽  
Outer Membrane ◽  
Gel Electrophoresis ◽  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
Cell Wall Component ◽  
Protein Components ◽  
Exposure Technique ◽  
Structural Aspects

The periodic structure external to the outer membrane of Spirillum serpens VHA has been isolated by similar procedures to those used by Buckmire and Murray (1). From SDS gel electrophoresis, we have found that the isolated fragments contain several protein components, and that the crystalline structure is composed of a glycoprotein component with a molecular weight of ∽ 140,000 daltons (2). Under an electron microscopic examination, we have visualized the hexagonally-packed glycoprotein subunits, as well as the bilayer profile of the outer membrane. In this paper, we will discuss some structural aspects of the crystalline glycoproteins, based on computer-reconstructed images of the external cell wall fragments.The specimens were prepared for electron microscopy in two ways: negatively stained with 1% PTA, and maintained in a frozen-hydrated state (3). The micrographs were taken with a JEM-100B electron microscope with a field emission gun. The minimum exposure technique was essential for imaging the frozen- hydrated specimens.

Autonomous self-healing polyisoprene elastomers with high modulus and good toughness based on the synergy of dynamic ionic crosslinks and highly disordered crystals

2020 ◽  
Vol 11 (41) ◽  
pp. 6549-6558
Author(s):  
Yohei Miwa ◽  
Mayu Yamada ◽  
Yu Shinke ◽  
Shoichi Kutsumizu
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Self Healing ◽  
High Modulus ◽  
Disordered Crystals ◽  
Ionic Crosslinks

We designed a novel polyisoprene elastomer with high mechanical properties and autonomous self-healing capability at room temperature facilitated by the coexistence of dynamic ionic crosslinks and crystalline components that slowly reassembled.

Congenital self-healing histiocytosis

1982 ◽  
Vol 118 (4) ◽  
pp. 267-272 ◽  
Author(s):  
E. Bonifazi
Keyword(s):  
Self Healing
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