scholarly journals Biomedical films of graphene nanoribbons and nanoflakes with natural polymers

RSC Advances ◽  
2017 ◽  
Vol 7 (44) ◽  
pp. 27578-27594 ◽  
Author(s):  
Magda Silva ◽  
Sofia G. Caridade ◽  
Ana C. Vale ◽  
Eunice Cunha ◽  
Maria P. Sousa ◽  
...  
Keyword(s):  
Graphene Nanoribbons ◽  
Layer By Layer ◽  
Natural Polymers ◽  
Free Standing

Novel nanostructured free-standing films based on chitosan, alginate and functionalized flake and ribbon-shaped graphene were developed using the layer-by-layer process.

scholarly journals High performance free-standing films by layer-by-layer assembly of graphene flakes and ribbons with natural polymers

2016 ◽  
Vol 4 (47) ◽  
pp. 7718-7730 ◽  
Author(s):  
D. Moura ◽  
S. G. Caridade ◽  
M. P. Sousa ◽  
E. Cunha ◽  
H. C. Rocha ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
High Performance ◽  
Layer By Layer ◽  
Natural Polymers ◽  
Free Standing ◽  
Layer By Layer Assembly ◽  
Graphene Flakes ◽  
Layer Assembly

In this work, novel free-standing (FS) films based on chitosan, alginate and graphene oxide (GO) were developed through layer-by-layer assembly.

From supramolecular chemistry to nanotechnology: Assembly of 3D nanostructures

2009 ◽  
Vol 81 (12) ◽  
pp. 2225-2233 ◽  
Author(s):  
Xing Yi Ling ◽  
David N. Reinhoudt ◽  
Jurriaan Huskens
Keyword(s):  
Supramolecular Chemistry ◽  
Self Assembly ◽  
Supramolecular Assembly ◽  
Fine Tuning ◽  
Nanoparticle Assembly ◽  
Layer By Layer ◽  
Surface Binding ◽  
Free Standing ◽  
Functionalized Nanoparticles ◽  
Assembled Monolayers

Fabricating well-defined and stable nanoparticle crystals in a controlled fashion receives growing attention in nanotechnology. The order and packing symmetry within a nanoparticle crystal is of utmost importance for the development of materials with unique optical and electronic properties. To generate stable and ordered 3D nanoparticle structures, nanotechnology is combined with supramolecular chemistry to control the self-assembly of 2D and 3D receptor-functionalized nanoparticles. This review focuses on the use of molecular recognition chemistry to establish stable, ordered, and functional nanoparticle structures. The host–guest complexation of β-cyclodextrin (CD) and its guest molecules (e.g., adamantane and ferrocene) are applied to assist the nanoparticle assembly. Direct adsorption of supramolecular guest- and host-functionalized nanoparticles onto (patterned) CD self-assembled monolayers (SAMs) occurs via multivalent host–guest interactions and layer-by-layer (LbL) assembly. The reversibility and fine-tuning of the nanoparticle-surface binding strength in this supramolecular assembly scheme are the control parameters in the process. Furthermore, the supramolecular nanoparticle assembly has been integrated with top-down nanofabrication schemes to generate stable and ordered 3D nanoparticle structures, with controlled geometries and sizes, on surfaces, other interfaces, and as free-standing structures.

Layer-by-layer self-assembly, controllable disintegration of polycarboxybetaine multilayers and preparation of free-standing films at physiological conditions

2010 ◽  
Vol 20 (8) ◽  
pp. 1467-1474 ◽  
Author(s):  
Zhangliang Gui ◽  
Jinwen Qian ◽  
Quanfu An ◽  
Qiang Zhao ◽  
Huangtao Jin ◽  
...  
Keyword(s):  
Self Assembly ◽  
Layer By Layer ◽  
Free Standing ◽  
Physiological Conditions

scholarly journals A Direct Comparison of Three Buckling-Based Methods to Measure the Elastic Modulus of Nanobiocomposite Thin Films

2020 ◽  
Author(s):  
Taylor C. Stimpson ◽  
Daniel A. Osorio ◽  
Emily D. Cranston ◽  
Jose Moran-Mirabal
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Mechanical Properties ◽  
Elastic Modulus ◽  
Elastic Moduli ◽  
Input Parameter ◽  
Layer By Layer ◽  
Free Standing ◽  
Film Composition ◽  
Parameter Values

<p>To engineer tunable thin film materials, accurate measurement of their mechanical properties is crucial. However, characterizing the elastic modulus with current methods is particularly challenging for sub-micrometer thick films and hygroscopic materials because they are highly sensitive to environmental conditions and most methods require free-standing films which are difficult to prepare. In this work, we directly compared three buckling-based methods to determine the elastic moduli of supported thin films: 1) biaxial thermal shrinking, 2) uniaxial thermal shrinking, and 3) the mechanically compressed, strain-induced elastic buckling instability for mechanical measurements (SIEBIMM) method. Nanobiocomposite model films composed of cellulose nanocrystals (CNCs) and polyethyleneimine (PEI) were assembled using layer-by-layer deposition to control composition and thickness. The three buckling-based methods yielded the same trends and comparable values for the elastic moduli of each CNC-PEI film composition (ranging from 15 – 44 GPa, depending on film composition). This suggests that the methods are similarly effective for the quantification of thin film mechanical properties. Increasing the CNC content in the films statistically increased the modulus, however, increasing the PEI content did not lead to significant changes. The standard deviation of elastic moduli determined from SIEBIMM was 2-4 times larger than for thermal shrinking, likely due to extensive cracking and partial film delamination. In light of these results, biaxial thermal shrinking is recommended as the method of choice because it affords the simplest implementation and analysis and is the least sensitive to small deviations in the input parameter values, such as film thickness or substrate modulus.</p>

scholarly journals Natural Polymers for 3D Bioprinting of Organs

2020 ◽  
pp. 30-40
Author(s):  
Galina Sroslova ◽  
Yuliya Zimina ◽  
Elena Nesmeyanova ◽  
Margarita Postnova
Keyword(s):  
Raw Materials ◽  
Sol Gel ◽  
Three Dimensional ◽  
Biologically Active ◽  
Artificial Organs ◽  
Gel Point ◽  
Layer By Layer ◽  
3D Bioprinting ◽  
Natural Polymers ◽  
Biological Origin

Three-dimensional (3D) bioprintingis a well-known promising technology for the production of artificial biological organs providing unprecedented versatility for manipulating cells and other biomaterials with precise control of their location in space. Over the past decade, a number of 3D bioprinting technologies have been developed. Unlike traditional manufacturing technologies, 3D bioprinting allows to produce individual or personalized fabric designs. This helps to deposit cells of the desired type with selected biomaterials and desired biologically active substances. Natural polymers play a leading role in maintaining cellular and biomolecular processes before, during, as well as after three-dimensional bioprinting. Polymers of biological origin can be extracted from natural raw materials by means of physical or chemical methods. These polymers are widely used as effective hydrogels for loading cells to form tissues, build a vascular, nervous, lymphatic network, and also to implement multiple biological, biochemical, physiological, biomedical and other functions. Any natural polymers that have a sol-gel phase transition (i.e., a gel point) under certain conditions can be printed using the automatic layer-by-layer deposition method. In fact, very few of them can be printed under various conditions (low temperature, without the help of physical, chemical, biochemical crosslinking of the incorporated polymer chains). Thus, not all natural polymers can meet all the basic requirements for 3D bioprinting. As a rule, natural polymers as the main component of various inks, which contain cells suspended in a specific medium, must meet several basic requirements for successful 3D bioprinting of organs, as well as clinical applications. These include biocompatibility, that is, non-toxic or without apparent toxicity; biodegradability (unlikenon-biodegradable polymers can be used as auxiliary structures); biostability with sufficiently high mechanical strength both at the time of processing and during operation; bioprinterness (workability). This review is devoted to modern research in the field of natural polymers used to print biological artificial organs.

scholarly journals A patterning-free approach for growth of free-standing graphene nanoribbons using step-bunched facets of off-oriented 4H-SiC(0 0 0 1) epilayers

2020 ◽  
Vol 53 (11) ◽  
pp. 115102
Author(s):  
Yuchen Shi ◽  
Alexei A Zakharov ◽  
Ivan G Ivanov ◽  
Nikolay A Vinogradov ◽  
G Reza Yazdi ◽  
...  
Keyword(s):  
Graphene Nanoribbons ◽  
Free Standing

Stabilization of Graphene Dispersions by Cellulose Nanocrystals Colloids

2018 ◽  
Author(s):  
Danny Illera ◽  
Chatura Wickramaratne ◽  
Diego Guillen ◽  
Chand Jotshi ◽  
Humberto Gomez ◽  
...  
Keyword(s):  
Energy Storage ◽  
Cellulose Nanocrystals ◽  
Large Scale ◽  
Single Layer Graphene ◽  
Graphene Sheets ◽  
Layer By Layer ◽  
Scale Production ◽  
Free Standing ◽  
Capacitive Energy Storage ◽  
Freeze Dried

The outstanding properties of single-layer graphene sheets for energy storage are hindered as agglomeration or restacking leads to the formation of graphite. The implications of the aforementioned arise on the difficulties associated with the aqueous processing of graphene sheets: from large-scale production to its utilization in solvent-assisted techniques like spin coating or layer-by-layer deposition. To overcome this, aqueous dispersions of graphene were stabilized by cellulose nanocrystals colloids. Aqueous cellulose nanocrystals dispersion highlights as a low-cost and environmentally friendly stabilizer towards graphene large-scale processing. Colloids of cellulose nanocrystals are formed by electrostatic repulsion of fibrils due to de-protonated carboxyl or sulfate half-ester functional groups. Graphene dispersions are obtained by hydrothermal reduction of electrochemically exfoliated graphene oxide in the presence of cellulose nanocrystals. This approach allows the preservation of the intrinsic properties of the nano-sheets by promoting non-covalent interactions between cellulose and graphene. The dispersions could be cast to form free-standing flexible conducting films or freeze-dried to form foams and aerogels for capacitive energy storage.

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