scholarly journals Eco-Friendly Chitosan@Silver/Plant Fiber Membranes for Masks with Thermal Comfortability and Self-Sterilization

2021 ◽  
Author(s):  
Qian Zou ◽  
Yinuo Gai ◽  
Xiaotang Gai ◽  
Siwei Xiong ◽  
Nanjun Wei ◽  
...  
Keyword(s):  
Room Temperature ◽  
Antibacterial Properties ◽  
Core Shell ◽  
Plant Fiber ◽  
Plant Fibers ◽  
Antiviral Effects ◽  
Surgical Masks ◽  
Long Time ◽  
Heavy Burden

Abstract The surgical masks have been essential consumables for public in the COVID-19 pandemic. However, long-time wearing masks will make wearers feel uncomfortable and massive discarded non-biodegradable masks lead to a heavy burden on our environment. In this paper, we adopt degradable chitosan@silver (CS@Ag) core-shell fibers and plant fibers to prepare an eco-friendly mask with excellent thermal comfort, self-sterilization, and antiviral effects. The thermal network of CS@Ag core-shell fibers highly improves the in-plane thermal conductivity of masks, which is 4.45 times higher than that of commercial masks. Because of the electrical conductivity of Ag, the fabricated mask can be electrically heated to warm the wearer in a cold environment and disinfect COVID-19 facilely at room temperature. Meanwhile, the in-situ reduced silver nanoparticles (AgNPs) endow the mask with superior antibacterial properties. Therefore, this mask shows a great potential to address the urgent need for a thermally comfortable, antibacterial, antiviral, and eco-friendly mask.

A BIO-INSPIRED POLYDOPAMINE APPROACH TO PREPARATION OF GOLD-COATED Fe3O4 CORE–SHELL NANOPARTICLES: SYNTHESIS, CHARACTERIZATION AND MECHANISM

NANO ◽  
2013 ◽  
Vol 08 (06) ◽  
pp. 1350061 ◽  
Author(s):  
PENG AN ◽  
FANG ZUO ◽  
XINHUA LI ◽  
YUANPENG WU ◽  
JUNHUA ZHANG ◽  
...  
Keyword(s):  
Shell Structure ◽  
Room Temperature ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Stabilizing Agent ◽  
X Ray ◽  
Transmission Electron ◽  
Core Shell Structure ◽  
Core Shell Nanoparticles

A biomimetic and facile approach for integrating Fe 3 O 4 and Au with polydopamine (PDA) was proposed to construct gold-coated Fe 3 O 4 nanoparticles ( Fe 3 O 4@ Au – PDA ) with a core–shell structure by coupling in situ reduction with a seed-mediated method in aqueous solution at room temperature. The morphology, structure and composition of the core–shell structured Fe 3 O 4@ Au – PDA nanoparticles were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and X-ray photoelectron spectrometry (XPS). The formation process of Au shell was assessed using a UV-Vis spectrophotometer. More importantly, according to investigating changes in PDA molecules by Fourier transform infrared spectroscopy (FTIR) and in preparation process of the zeta-potential data of nanoparticles, the mechanism of core–shell structure formation was proposed. Firstly, PDA-coated Fe 3 O 4 are obtained using dopamine (DA) self-polymerization to form thin and surface-adherent PDA films onto the surface of a Fe 3 O 4 "core". Then, Au seeds are attached on the surface of PDA-coated Fe 3 O 4 via electrostatic interaction in order to serve as nucleation centers catalyzing the reduction of Au 3+ to Au 0 by the catechol groups in PDA. Accompanied by the deposition of Au , PDA films transfer from the surface of Fe 3 O 4 to that of Au as stabilizing agent. In order to confirm the reasonableness of this mechanism, two verification experiments were conducted. The presence of PDA on the surface of Fe 3 O 4@ Au – PDA nanoparticles was confirmed by the finding that glycine or ethylenediamine could be grafted onto Fe 3 O 4@ Au – PDA nanoparticles through Schiff base reaction. In addition, Fe 3 O 4@ Au – DA nanoparticles, in which DA was substituted for PDA, were prepared using the same method as that for Fe 3 O 4@ Au – PDA nanoparticles and characterized by UV-Vis, TEM and FTIR. The results validated that DA possesses multiple functions of attaching Au seeds as well as acting as both reductant and stabilizing agent, the same functions as those of PDA.

scholarly journals Atmospheric Pressure Microplasma for Antibacterial Silver Nanoparticle/Chitosan Nanocomposites With Tailored Properties

2019 ◽  
Author(s):  
Daye Sun ◽  
Jonathan Turner ◽  
Nan Jiang ◽  
Songsong Zhu ◽  
Li Zhang ◽  
...  
Keyword(s):  
Silver Nanoparticle ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Polymer Network ◽  
Antibacterial Properties ◽  
Bacterial Strains ◽  
E Coli ◽  
Modified Chitosan ◽  
First Time

<p>Room temperature atmospheric pressure microplasma (APM) was deployed for the first time for the in situ synthesis of anti-bacterial silver nanoparticle / chitosan (AgNP/CS) nanocomposites. The plasma induced liquid chemistry plays a role in the in situ formation of AgNP, the size distribution of which depends on the silver salt precursor concentration. The microplasma process has also simultaneously tailored the physical properties of the composites, rendering more crosslinked chitosan polymer network with shorter molecular chains. The formation of AgNP within the <i>in situ</i> modified chitosan has led to nanocomposites with overall improved mechanical properties and better stability in simulated body fluid. Our plasma synthesized AgNP/CS nanocomposites also demonstrate effective antibacterial properties against <i>E. Coli</i> and <i>S. Aureus</i> bacterial strains, showing their promise in potential antimicrobial applications.</p>

Cu2O@Fe–Ni3S2 nanoflower in situ grown on copper foam at room temperature as an excellent oxygen evolution electrocatalyst

2020 ◽  
Vol 56 (82) ◽  
pp. 12339-12342
Author(s):  
Li Li Wu ◽  
Yu Xian Yang ◽  
Xiao Hui Chen ◽  
Juan Luo ◽  
Hong Chuan Fu ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Water Oxidation ◽  
Room Temperature ◽  
Core Shell ◽  
Copper Foam

A 3D/2D core–shell Cu2O@Fe–Ni3S2 nanoflower is prepared at room temperature through an etching precipitation strategy for enhanced electrochemical water oxidation.

scholarly journals Atmospheric Pressure Microplasma for Antibacterial Silver Nanoparticle/Chitosan Nanocomposites With Tailored Properties

2019 ◽  
Author(s):  
Daye Sun ◽  
Jonathan Turner ◽  
Nan Jiang ◽  
Songsong Zhu ◽  
Li Zhang ◽  
...  
Keyword(s):  
Silver Nanoparticle ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Polymer Network ◽  
Antibacterial Properties ◽  
Bacterial Strains ◽  
E Coli ◽  
Modified Chitosan ◽  
First Time

<p>Room temperature atmospheric pressure microplasma (APM) was deployed for the first time for the in situ synthesis of anti-bacterial silver nanoparticle / chitosan (AgNP/CS) nanocomposites. The plasma induced liquid chemistry plays a role in the in situ formation of AgNP, the size distribution of which depends on the silver salt precursor concentration. The microplasma process has also simultaneously tailored the physical properties of the composites, rendering more crosslinked chitosan polymer network with shorter molecular chains. The formation of AgNP within the <i>in situ</i> modified chitosan has led to nanocomposites with overall improved mechanical properties and better stability in simulated body fluid. Our plasma synthesized AgNP/CS nanocomposites also demonstrate effective antibacterial properties against <i>E. Coli</i> and <i>S. Aureus</i> bacterial strains, showing their promise in potential antimicrobial applications.</p>

Electrical performance and stability of polypyrrole coated PET fibres

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Alessio Varesano ◽  
Anna Ibarzabal Ferrer ◽  
Claudio Tonin
Keyword(s):  
Aqueous Solution ◽  
Thermal Properties ◽  
Room Temperature ◽  
In Situ Polymerization ◽  
Electrical Performance ◽  
Different Temperatures ◽  
Long Time ◽  
Conducting Polypyrrole ◽  
Resistance To Heat

AbstractPET non-wovens were treated with intrinsically electro-conducting polypyrrole (PPy) produced by chemical oxidative in situ polymerization from pyrrole aqueous solution, using Fe3+ or S2O82- as oxidant, and different dopants. The resulting materials have different electrical performances and thermal properties depending on the thickness of the PPy coating, the amount and the type of dopant embedded into the polymer layer, the type of oxidant used and the pH of the polymerization bath. Samples were maintained at different temperatures and humidity with the aim of gathering information about the electrical performance stability in different environmental conditions. Generally, PPy shows conductivity decay when maintained at high temperature, whereas the conductivity slightly decreases when stored for a long time at cold or room temperature. Moreover, the PPy coating enhances the resistance to heat of the PET fibres (i.e. increase in melting temperature).

Synthesis of core–shell Au–Pt nanodendrites with high catalytic performance via overgrowth of platinum on in situ gold nanoparticles

2015 ◽  
Vol 3 (1) ◽  
pp. 368-376 ◽  
Author(s):  
Yijing Li ◽  
Wenchao Ding ◽  
Mingrui Li ◽  
Haibing Xia ◽  
Dayang Wang ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Room Temperature ◽  
Catalytic Performance ◽  
Core Shell

Well-dispersed, core–shell Au–Pt nanodendrites were synthesized via overgrowth of platinum on in situ 5.5 nm gold nanoparticles at room temperature.

Otoconia perfect/imperfect crystals

1994 ◽  
Vol 52 ◽  
pp. 42-43
Author(s):  
César D. Fermin ◽  
Dale Martin
Keyword(s):  
Image Processing ◽  
Room Temperature ◽  
Phosphotungstic Acid ◽  
Gallus Domesticus ◽  
Crystal Matrix ◽  
Organic Templates ◽  
Image Processing Algorithms ◽  
Processing Algorithms ◽  
Diffraction Patterns

Otoconia of higher vertebrates are interesting biological crystals that display the diffraction patterns of perfect crystals (e.g., calcite for birds and mammal) when intact, but fail to produce a regular crystallographic pattern when fixed. Image processing of the fixed crystal matrix, which resembles the organic templates of teeth and bone, failed to clarify a paradox of biomineralization described by Mann. Recently, we suggested that inner ear otoconia crystals contain growth plates that run in different directions, and that the arrangement of the plates may contribute to the turning angles seen at the hexagonal faces of the crystals.Using image processing algorithms described earlier, and Fourier Transform function (2FFT) of BioScan Optimas®, we evaluated the patterns in the packing of the otoconia fibrils of newly hatched chicks (Gallus domesticus) inner ears. Animals were fixed in situ by perfusion of 1% phosphotungstic acid (PTA) at room temperature through the left ventricle, after intraperitoneal Nembutal (35mg/Kg) deep anesthesia. Negatives were made with a Hitachi H-7100 TEM at 50K-400K magnifications. The negatives were then placed on a light box, where images were filtered and transferred to a 35 mm camera as described.

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