scholarly journals Recent progress to construct calixarene-based polymers using covalent bonds: synthesis and applications

RSC Advances ◽  
2020 ◽  
Vol 10 (54) ◽  
pp. 32690-32722
Author(s):  
Reza Zadmard ◽  
Fahimeh Hokmabadi ◽  
Mohammad Reza Jalali ◽  
Ali Akbarzadeh
Keyword(s):  
Supramolecular Chemistry ◽  
Recent Progress ◽  
Covalent Bonds ◽  
Great Possibility

The combination of supramolecular chemistry and polymer sciences creates a great possibility to afford calixarene-based polymers offering unique features and applications.

Recent progress in dynamic covalent chemistries for liquid crystal elastomers

2020 ◽  
Vol 8 (31) ◽  
pp. 6610-6623 ◽  
Author(s):  
Zhijian Wang ◽  
Shengqiang Cai
Keyword(s):  
Liquid Crystal ◽  
Recent Progress ◽  
Review Article ◽  
Covalent Bonds ◽  
Liquid Crystal Elastomers

This review article discusses the recent progress in designing, synthesizing and programming liquid crystal elastomers with different dynamic covalent bonds.

scholarly journals Recent Progress in 3D Printing of Elastic and High-Strength Hydrogels for the Treatment of Osteochondral and Cartilage Diseases

2020 ◽  
Vol 8 ◽  
Author(s):  
Wenli Dai ◽  
Muyang Sun ◽  
Xi Leng ◽  
Xiaoqing Hu ◽  
Yingfang Ao
Keyword(s):  
Articular Cartilage ◽  
3D Printing ◽  
Recent Progress ◽  
High Strength ◽  
Cartilage Defects ◽  
High Water Content ◽  
Covalent Bonds ◽  
Cartilage Diseases ◽  
Articular Cartilage Defects ◽  
And Cartilage

Despite considerable progress for the regenerative medicine, repair of full-thickness articular cartilage defects and osteochondral interface remains challenging. This low efficiency is largely due to the difficulties in recapitulating the stratified zonal architecture of articular cartilage and engineering complex gradients for bone-soft tissue interface. This has led to increased interest in three-dimensional (3D) printing technologies in the field of musculoskeletal tissue engineering. Printable and biocompatible hydrogels are attractive materials for 3D printing applications because they not only own high tunability and complexity, but also offer favorable biomimetic environments for live cells, such as porous structure, high water content, and bioactive molecule incorporation. However, conventional hydrogels are usually mechanically weak and brittle, which cannot reach the mechanical requirements for repair of articular cartilage defects and osteochondral interface. Therefore, the development of elastic and high-strength hydrogels for 3D printing in the repairment of cartilage defects and osteochondral interface is crucial. In this review, we summarized the recent progress in elastic and high-strength hydrogels for 3D printing and categorized them into six groups, namely ion bonds interactions, nanocomposites integrated in hydrogels, supramolecular guest–host interactions, hydrogen bonds interactions, dynamic covalent bonds interactions, and hydrophobic interactions. These 3D printed elastic and high-strength hydrogels may provide new insights for the treatment of osteochondral and cartilage diseases.

Method for Fabricating Arrays of Graphene Nanoribbons

2011 ◽  
Vol 1362 ◽  
Author(s):  
Pavel Khokhlov ◽  
Pavel Lazarev ◽  
Evgeny Morozov
Keyword(s):  
Thin Film Transistors ◽  
Recent Progress ◽  
Organic Molecules ◽  
Graphene Nanoribbons ◽  
Film Surface ◽  
Covalent Bonds ◽  
Ordered Arrays ◽  
Tribological Coatings ◽  
Smooth Film ◽  
Made In

ABSTRACTThis paper discusses recent progress made in developing an advanced sp2 carbon-based materials that can be produced by wet coating as a thin layer and processed to form highly ordered arrays of Graphene Nanoribbons (GNRs) that attach to the substrate on edge with their planes parallel to each other. The fabrication method is based on carbonization of organic molecules spatially preordered in crystalline film on the substrate. This material, named Ribtan, can be used to fabricate GNRs films over large areas that exhibit a very smooth film surface and can form strong covalent bonds to the substrate. The width (film thickness) of Ribtan GNRs can be controlled precisely down to a few nanometers. We demonstrated advantage of Ribtan material for application in supercapacitors as well as feasibility for use in transparent electrodes, solid tribological coatings, and thin film transistors.

Recent aspects of self-oscillating polymeric materials: designing self-oscillating polymers coupled with supramolecular chemistry and ionic liquid science

2014 ◽  
Vol 16 (22) ◽  
pp. 10388-10397 ◽  
Author(s):  
Takeshi Ueki ◽  
Ryo Yoshida
Keyword(s):  
Ionic Liquid ◽  
Supramolecular Chemistry ◽  
Polymeric Materials ◽  
Building Blocks ◽  
Covalent Bonds ◽  
Spatiotemporal Structure ◽  
Molecular Building Blocks ◽  
Recent Developments

Herein, we summarise the recent developments in self-oscillating polymeric materials based on the concepts of supramolecular chemistry, where aggregates of molecular building blocks with non-covalent bonds evolve the temporal or spatiotemporal structure.

scholarly journals Recent Advances of Hierarchical and Sequential Growth of Macromolecular Organic Structures on Surface

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 662 ◽  
Author(s):  
Corentin Pigot ◽  
Frédéric Dumur
Keyword(s):  
Supramolecular Chemistry ◽  
Data Storage ◽  
Materials Science ◽  
Growth Control ◽  
Linear Polymers ◽  
Research Activity ◽  
Covalent Bonds ◽  
New Approach ◽  
Promising Strategy ◽  
Important Milestone

The fabrication of macromolecular organic structures on surfaces is one major concern in materials science. Nanoribbons, linear polymers, and porous nanostructures have gained a lot of interest due to their possible applications ranging from nanotemplates, catalysis, optoelectronics, sensors, or data storage. During decades, supramolecular chemistry has constituted an unavoidable approach for the design of well-organized structures on surfaces displaying a long-range order. Following these initial works, an important milestone has been established with the formation of covalent bonds between molecules. Resulting from this unprecedented approach, various nanostructures of improved thermal and chemical stability compared to those obtained by supramolecular chemistry and displaying unique and unprecedented properties have been developed. However, a major challenge exists: the growth control is very delicate and a thorough understanding of the complex mechanisms governing the on-surface chemistry is still needed. Recently, a new approach consisting in elaborating macromolecular structures by combining consecutive steps has been identified as a promising strategy to elaborate organic structures on surface. By designing precursors with a preprogrammed sequence of reactivity, a hierarchical or a sequential growth of 1D and 2D structures can be realized. In this review, the different reaction combinations used for the design of 1D and 2D structures are reported. To date, eight different sequences of reactions have been examined since 2008, evidencing the intense research activity existing in this field.

scholarly journals Nanocomposite bioink exploits dynamic covalent bonds between nanoparticles and polysaccharides for precision bioprinting

2019 ◽  
Author(s):  
Mihyun Lee ◽  
Kraun Bae ◽  
Clara Levinson ◽  
Marcy Zenobi-Wong
Keyword(s):  
Mechanical Strength ◽  
Rheological Properties ◽  
Yield Stress ◽  
Recent Progress ◽  
Mechanical Stability ◽  
Covalent Bonds ◽  
Good Biocompatibility

AbstractThe field of bioprinting has made significant recent progress towards engineering tissues with increasing complexity and functionality. It remains challenging, however, to develop bioinks with optimal biocompatibility and good printing fidelity. Here, we demonstrate enhanced printability of a polymer-based bioink based on dynamic covalent linkages between nanoparticles (NPs) and polymers, which retains good biocompatibility. Amine-presenting silica NPs (ca. 45 nm) were added to a polymeric ink containing oxidized alginate (OxA). The formation of reversible imine bonds between amines on the NPs and aldehydes of OxA lead to significantly improved rheological properties and high printing fidelity. In particular, the yield stress increased with increasing amounts of NPs (14.5 Pa without NPs, 79 Pa with 2 wt% NPs). In addition, the presence of dynamic covalent linkages in the gel provided improved mechanical stability over 7 days compared to ionically crosslinked gels. The nanocomposite ink retained high printability and mechanical strength, resulting in generation of centimetre-scale porous constructs and an ear structure with overhangs and high structural fidelity. Furthermore, the nanocomposite ink supported both in vitro and in vivo maturation of bioprinted gels containing chondrocytes. This approach based on simple oxidation can be applied to any polysaccharide, thus the widely applicability of the method is expected to advance the field towards the goal of precision bioprinting.

Supramolecular design in 2D covalent organic frameworks

2020 ◽  
Vol 49 (5) ◽  
pp. 1344-1356 ◽  
Author(s):  
Sampath B. Alahakoon ◽  
Shashini D. Diwakara ◽  
Christina M. Thompson ◽  
Ronald A. Smaldone
Keyword(s):  
Supramolecular Chemistry ◽  
Porous Polymers ◽  
Covalent Organic Frameworks ◽  
Covalent Bonds ◽  
Crystalline Structures ◽  
Form And Function ◽  
And Function

2D covalent organic frameworks (COFs) are a class of porous polymers with crystalline structures. This tutorial review discusses how the concepts of supramolecular chemistry are used to add form and function to COFs through their non-covalent bonds.

scholarly journals Covalent Organic Frameworks: A Promising Materials Platform for Photocatalytic CO2 Reductions

Molecules ◽  
2020 ◽  
Vol 25 (10) ◽  
pp. 2425
Author(s):  
Jundan Li ◽  
Dongni Zhao ◽  
Jiangqun Liu ◽  
Anan Liu ◽  
Dongge Ma
Keyword(s):  
Recent Progress ◽  
State Of The Art ◽  
Co2 Reduction ◽  
Research Field ◽  
High Thermal Stability ◽  
Three Dimensions ◽  
Covalent Organic Frameworks ◽  
Covalent Bonds ◽  
Good Crystallinity ◽  
Future Direction

Covalent organic frameworks (COFs) are a kind of porous crystalline polymeric material. They are constructed by organic module units connected with strong covalent bonds extending in two or three dimensions. COFs possess the advantages of low-density, large specific surface area, high thermal stability, developed pore-structure, long-range order, good crystallinity, and the excellent tunability of the monomer units and the linking reticular chemistry. These features endowed COFs with the ability to be applied in a plethora of applications, ranging from adsorption and separation, sensing, catalysis, optoelectronics, energy storage, mass transport, etc. In this paper, we will review the recent progress of COFs materials applied in photocatalytic CO2 reduction. The state-of-the-art paragon examples and the current challenges will be discussed in detail. The future direction in this research field will be finally outlooked.

Temperature Dependence of the Critical Electron Dose for Fatty Acid Monolayers

1982 ◽  
Vol 40 ◽  
pp. 78-79
Author(s):  
Kenneth H. Downing ◽  
Robert M. Glaeser
Keyword(s):  
Electron Beam ◽  
Fatty Acid ◽  
Inelastic Scattering ◽  
Temperature Dependence ◽  
Structural Damage ◽  
Direct Result ◽  
Second Step ◽  
Strong Temperature Dependence ◽  
Electron Dose ◽  
Covalent Bonds

The structural damage of molecules irradiated by electrons is generally considered to occur in two steps. The direct result of inelastic scattering events is the disruption of covalent bonds. Following changes in bond structure, movement of the constituent atoms produces permanent distortions of the molecules. Since at least the second step should show a strong temperature dependence, it was to be expected that cooling a specimen should extend its lifetime in the electron beam. This result has been found in a large number of experiments, but the degree to which cooling the specimen enhances its resistance to radiation damage has been found to vary widely with specimen types.

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