scholarly journals Electrospun Multiple-Chamber Nanostructure and Its Potential Self-Healing Applications

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2413 ◽  
Author(s):  
Yubo Liu ◽  
Xinkuan Liu ◽  
Ping Liu ◽  
Xiaohong Chen ◽  
Deng-Guang Yu
Keyword(s):  
Electron Microscope ◽  
Electrochemical Corrosion ◽  
Average Diameter ◽  
Self Healing ◽  
Scanning Calorimetry ◽  
Uniform Size ◽  
Transmission Electron ◽  
Reactive Fluids ◽  
Amine Curing ◽  
First Time

To address the life span of materials in the process of daily use, new types of structural nanofibers, fabricated by multifluid electrospinning to encapsulate both epoxy resin and amine curing agent, were embedded into an epoxy matrix to provide it with self-healing ability. The nanofibers, which have a polyacrylonitrile sheath holding two separate cores, had an average diameter of 300 ± 140 nm with a uniform size distribution. The prepared fibers had a linear morphology with a clear three-chamber inner structure, as verified by scanning electron microscope and transmission electron microscope images. The two core sections were composed of epoxy and amine curing agents, respectively, as demonstrated under the synergistic characterization of Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry. The TGA results disclosed that the core-shell nanofibers contained 9.06% triethylenetetramine and 20.71% cured epoxy. In the electrochemical corrosion experiment, self-healing coatings exhibited an effective anti-corrosion effect, unlike the composite without nanofibers. This complex nanostructure was proven to be an effective nanoreactor, which is useful to encapsulate reactive fluids. This engineering process by multiple-fluid electrospinning is the first time to prove that this special multiple-chamber structure has great potential in the field of self-healing.

Preparation of a monodisperse poly (N-phenylmaleimide–acrylonitrile–styrene) structural nanolatex for heat-resistant modification of PVC

2018 ◽  
Vol 32 (3) ◽  
pp. 409-423
Author(s):  
Jin Wang ◽  
Hua Qiu ◽  
Bo Cheng ◽  
Fan Zhang ◽  
Shuhua Qi
Keyword(s):  
Electron Microscope ◽  
Elemental Analysis ◽  
Hybrid Composite ◽  
Average Diameter ◽  
Microemulsion Polymerization ◽  
Scanning Calorimetry ◽  
Thermogravimetric Analyzer ◽  
Melt Compounding ◽  
Transmission Electron ◽  
Ftir Spectrometer

A monodisperse poly ( N-phenylmaleimide–acrylonitrile–styrene) (PNAS) nanolatex was synthesized via seed microemulsion polymerization. The obtained PNAS nanolatex was then directly used as an organic nanofiller to prepare polyvinyl chloride (PVC)/PNAS hybrid composite through water blending and melt compounding. The characteristics of PNAS nanolatex were analyzed by Fourier transform infrared (FTIR) spectrometer, elemental analysis, scanning electron microscope, transmission electron microscope (TEM), dynamic laser lighting scattering (DLS), differential scanning calorimetry (DSC), and thermogravimetric analyzer (TGA). FTIR and elemental analysis confirmed the formation of PNAS copolymer with high monomers conversion; meanwhile, for the PNAS nanoparticles, the morphology of a well-defined core–shell spherical structure with average diameter ranging from 156 nm to 249 nm was observed. DSC analysis and TGA indicated that both polymers had excellent compatibility, and the corresponding heat resistance of PVC was greatly improved with the addition of PNAS. When PNAS loading was 50 wt%, the glass transition temperature value of PVC/PNAS hybrid composite was increased by 22.4°C, compared with that of pristine PVC. The mechanical properties of the PVC composite were also enhanced with the addition of PNAS.

Solvothermal Synthesis of Bi2Se3 Hexagonal Nanosheet Crystals

2011 ◽  
Vol 236-238 ◽  
pp. 1712-1716 ◽  
Author(s):  
Hai Tao Liu ◽  
Jun Dai ◽  
Jia Jia Zhang ◽  
Wei Dong Xiang
Keyword(s):  
Electron Microscope ◽  
Solvothermal Synthesis ◽  
Solvothermal Method ◽  
Raw Materials ◽  
X Ray Diffraction ◽  
Uniform Size ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Scanning Electron

Bismuth selenide (Bi2Se3) hexagonal nanosheet crystals with uniform size were successfully prepared via a solvothermal method at 160°C for 22 h using bismuth trichloride(BiCl3) and selenium powder(Se) as raw materials, sodium bisulfite(NaHSO3) as a reducing agent, diethylene glycol(DEG) as solvent, and ammonia as pH regulator. Various techniques such as X-ray diffraction (XRD), field-emission scanning electron microscope (FESEM), high-resolution transmission electron microscope (HRTEM), and selected area electron diffraction (SAED) were used to characterize the obtained products. Results show that the as-synthesized samples are pure Bi2Se3 hexagonal nanosheet crystals. A possible growth mechanism for Bi2Se3 hexagonal nanosheet crystals is also discussed based on the experiment.

Ultrastructural evidence of sperm dimorphism in Deladenus sp. (Tylenchomorpha: Sphaerularioidea: Allantonematidae)

Nematology ◽  
2007 ◽  
Vol 9 (3) ◽  
pp. 397-404 ◽  
Author(s):  
Hajime Kosaka ◽  
Manabu Kusunoki ◽  
Vladimir Yushin
Keyword(s):  
Electron Microscope ◽  
Parasitic Nematode ◽  
Spermatogenic Cells ◽  
Ultrastructural Evidence ◽  
Transmission Electron ◽  
Parallel Fibres ◽  
Sperm Dimorphism ◽  
Whole Life Cycle ◽  
First Time ◽  
Spherical Vesicles

AbstractThe dimorphic spermatozoa of the insect-parasitic nematode Deladenus sp. (Tylenchomorpha: Sphaerularioidea: Allantonematidae) were studied for the first time with a transmission electron microscope (TEM). The immature spermatozoa from the testis of mycetophagous males are 10-12 μm diam. and 4-5 μm long unpolarised cells with a centrally located nucleus without a nuclear envelope. The cytoplasm contains mitochondria and specific components, membranous organelles (MO) and fibrous bodies (FB). The MO are spherical vesicles with an internal system of finger-like invaginations of the membrane; the spindle-shaped FB consist of tightly packed parallel fibres. Spermatozoa from the uteri of infective females of Deladenus sp. are vastly different in size being tiny cells ca 2 μm diam. with a spherical or oval nucleus. Each cell contains several mitochondria and MO. Although each individual of Deladenus sp. contains only monomorphic spermatozoa, sperm dimorphism was revealed after analysis of the whole life cycle. Despite a difference in size the cytological characters of both types of spermatozoa conform to the typical rhabditid pattern. The presence of both MO and FB in sphaerularioidid spermatozoa differentiates the superfamily Sphaerularioidea from Tylenchoidea whose representatives lack MO in the spermatogenic cells.

scholarly journals Comparison of the Growth and Thermal Properties of Nonwoven Polymers after Atomic Layer Deposition and Vapor Phase Infiltration

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1028
Author(s):  
Laura Keskiväli ◽  
Pirjo Heikkilä ◽  
Eija Kenttä ◽  
Tommi Virtanen ◽  
Hille Rautkoski ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Electron Microscope ◽  
Atomic Layer Deposition ◽  
Atomic Layer ◽  
Scanning Transmission Electron Microscope ◽  
Scanning Calorimetry ◽  
Polymeric Surfaces ◽  
Transmission Electron ◽  
Layer Deposition ◽  
Scanning Transmission

The growth mechanism of Atomic Layer Deposition (ALD) on polymeric surfaces differs from growth on inorganic solid substrates, such as silicon wafer or glass. In this paper, we report the growth experiments of Al2O3 and ZnO on nonwoven poly-L-lactic acid (PLLA), polyethersulphone (PES) and cellulose acetate (CA) fibres. Material growth in both ALD and infiltration mode was studied. The structures were examined with a scanning electron microscope (SEM), scanning transmission electron microscope (STEM), attenuated total reflectance-fourier-transform infrared spectroscopy (ATR-FTIR) and 27Al nuclear magnetic resonance (NMR). Furthermore, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis were used to explore the effect of ALD deposition on the thermal properties of the CA polymer. According to the SEM, STEM and ATR-FTIR analysis, the growth of Al2O3 was more uniform than ZnO on each of the polymers studied. In addition, according to ATR-FTIR spectroscopy, the infiltration resulted in interactions between the polymers and the ALD precursors. Thermal analysis (TGA/DSC) revealed a slower depolymerization process and better thermal resistance upon heating both in ALD-coated and infiltrated fibres, more pronounced on the latter type of structures, as seen from smaller endothermic peaks on TA.

Polymorphic SERPINA3-R124C reduces pathogenesis of its wild type by shortening the life time of oligomeric Aβ

2021 ◽  
Author(s):  
Maruf Mohammad Akbor ◽  
Nobuyuki Kurosawa ◽  
Masashi Tanaka ◽  
Masaharu Isobe
Keyword(s):  
Cell Death ◽  
Electron Microscope ◽  
Alzheimer Disease ◽  
Life Time ◽  
Serine Protease Inhibitor ◽  
Wild Type ◽  
Western Blot Assay ◽  
Transmission Electron ◽  
First Time ◽  
Β Sheet

Abstract Amyloid beta (Aβ) 42 peptide accumulated in Alzheimer disease (AD) patients’ brain, often colocalized with serine protease inhibitor family A member 3 (SERPINA3). Being a chaperon, SERPINA3 accelerated Aβ42 fibrillization. While analyzing chaperon activity of human SERPINA3 polymorphisms, we found SERPINA3-R124C played a role in protecting cells from Aβ42 cytotoxicity. SH-SY5Y cells exposed to Aβ42 preincubated with wild type SERPINA3 (SERPINA3-WT) resulted in extended toxicity leading cell death whereas Aβ42 with SERPINA3-R124C resulted in less cytotoxicity. Transmission electron microscope and thioflavin T assay revealed that SERPINA3-R124C shortened life time of small soluble oligomer and maintained β-sheet rich protofibril-like aggregates for longer time compared to that of with SERPINA3-WT. Western blot assay confirmed that SERPINA3-R124C converted Aβ42 mostly into high molecular aggregates. Here, we demonstrate first time that polymorphic SERPINA3 acts as a benign chaperon by modulating the transition states of Aβ42, which may contribute to the reduction of AD risk.

SYNTHESIS OF CATALYST-FREE AND TEMPERATURE CONTROLLED MORPHOLOGIES OF CARBON NANOSTRUCTURES USING BOTANICAL HYDROCARBON: CASTOR OIL

NANO ◽  
2011 ◽  
Vol 06 (03) ◽  
pp. 215-223 ◽  
Author(s):  
RAJESH KUMAR ◽  
R. S. TIWARI ◽  
O. N. SRIVASTAVA
Keyword(s):  
Electron Microscope ◽  
Castor Oil ◽  
Carbon Nanoparticles ◽  
Carbon Nanostructures ◽  
Tubular Structure ◽  
Carbon Nanostructure ◽  
Uniform Size ◽  
Carbon Particles ◽  
Transmission Electron ◽  
Botanical Hydrocarbon

Castor oil (combination of fatty acids) precursor containing hydrocarbon with less amount of oxygen is used first time for synthesis of different carbon nanostructures (i.e., agglomerated carbon nanoparticles, carbon nanobeads and carbon tubular structure). The agglomerated carbon nanoparticles, carbon nanobeads and carbon tubular structure were synthesized by applying CVD method at different temperature using castor oil as new carbon precursor without any catalyst. The synthesis of carbon nanostructure is free from additional catalyst as this hydrocarbon (castor oil) is cheap with abundant sources of carbon. The effect of pyrolysis temperatures on the size, quality and quantity of the synthesized carbon shape were investigated. Interestingly, the morphology of the carbon nanostructures can be controlled in shape from agglomerated carbon nanoparticle to nanobeads to carbon tubular structure just by increasing the temperature from 750°C to 800°C to 850°C, respectively. These nanobeads are chains of uniform size of graphitized carbon spheres. These chains comprised individual carbon particles size of ~ 450 nm. The products were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), Raman spectroscopy and Fourier transform infrared spectroscopy (FTIR).

PREPARATION, CHARACTERIZATION AND LUMINESCENCE PROPERTIES OF Eu DOPED CaAl2O4 NANOCONES

2013 ◽  
Vol 27 (19) ◽  
pp. 1341018 ◽  
Author(s):  
J. M. LIANG ◽  
L. L. HE ◽  
Z. Q. SHEN ◽  
D. L. ZHANG
Keyword(s):  
Electron Microscope ◽  
Room Temperature ◽  
Thermal Evaporation ◽  
The Body ◽  
Monoclinic Structure ◽  
Thermal Evaporation Method ◽  
Room Temperature Photoluminescence ◽  
Spectrum Measurement ◽  
Transmission Electron ◽  
First Time

Europium doped CaAl 2 O 4 nanocones have been grown first time by thermal evaporation method. Scanning electron microscope (SEM) and transmission electron microscope (TEM) were used to analyze the morphology, size and crystal structure of the nanocones. The body of the nanocones are about 2–20 μm in length and their diameters are 200 nm to 1 μm at one end and tapers off to a ~ 40–200 nm at the tip end. The as-synthesized nanocones are single crystalline in monoclinic structure and grow along the [010] direction and the normal direction of (100) and (001). The room temperature photoluminescence (PL) and cathodoluminescence (CL) spectrum measurement reveals that CaAl 2 O 4: Eu 2+ nanocones emit light at about 440 nm.

scholarly journals First identification of nanoparticles on thorax, abdomen and wings of the worker bee Apis dorsata Fabricius

2016 ◽  
Vol 60 (1) ◽  
pp. 87-96
Author(s):  
Atanu Bhattacharyya ◽  
Shashidhar Viraktamath ◽  
Fani Hatjina ◽  
Santanu Bhattacharyya ◽  
Bhaktibhavana Rajankar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Average Diameter ◽  
The Body ◽  
Apis Dorsata ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Calcium Phosphate Nanoparticles ◽  
First Time

Abstract The presence of nanoparticles on the body of the honeybee Apis dorsata Fabricius, was investigated for the first time to better understand the bee’s behaviour. These have been observed by using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and confirmed by Atomic Force Microscopy (AFM). Our study clearly denotes that the Indian rock honey bee Apis dorsata possess calcium silicate and calcium phosphate nanoparticles on its body surface of 5-50 nm in diameter. In particular, the nanoparticles on the abdomen and thorax of A. dorsata have an average diameter of about 10 nanometers and they are smaller than those found on wings of the same bees which are about 20 nanometers. The nanoparticles found are different of the ones previously observed on honey bees or other insects. The origin and role of these natural nanoparticles on the body of the Indian rock bee need to be to be further investigated; more research in the subject might raise important aspects in relation to the conservation of these unique pollinators.

Photoluminescence of 10H-SiC

2016 ◽  
Vol 858 ◽  
pp. 269-273
Author(s):  
Anne Henry ◽  
Hiroshi Yano ◽  
Tomoaki Hatayama
Keyword(s):  
Electron Microscope ◽  
Band Gap ◽  
Transmission Electron Microscope ◽  
Lower Energy ◽  
Free Exciton ◽  
Binding Energies ◽  
Photoluminescence Spectra ◽  
Transmission Electron ◽  
First Time

The photoluminescence of the near band gap emission of 10H-SiC is revealed for the first time and detected just below 3.0 eV. The crystallinity thus polytype of the sample is controlled with transmission electron microscope analyses and Laue diffraction. On the photoluminescence spectra up to eight sharp lines are associated to the non-phonon lines of the nitrogen bound exciton even if ten are expected in 10H-SiC. Phonon replicas of these non-phonon lines are observed at lower energy with energy separations similar than those in other hexagonal SiC polytypes. At moderate temperature free-exciton replicas are also observed which allow the determination of the excitonic band gap at 3020.6 meV, value in agreement with the hexagonality of 10H-SiC of 40%. The binding energies associated to the nitrogen bound-excitons are determined as well as the ionization energies of the nitrogen donors in the 10H-SiC polytype.

Thermal transport, thermomechanical, and dielectric properties of chalcogenide Se98–xAg2Inx (x = 0, 2, 4, 6) system

2014 ◽  
Vol 92 (7/8) ◽  
pp. 648-653
Author(s):  
C. Dohare ◽  
N. Mehta
Keyword(s):  
Dielectric Constant ◽  
Electron Microscope ◽  
Dielectric Loss ◽  
Thermal Transport ◽  
Microstructural Analysis ◽  
Thermomechanical Properties ◽  
X Ray Diffraction ◽  
Glassy System ◽  
Scanning Calorimetry ◽  
Transmission Electron

The present work reports a detailed study of some physical properties of some novel glasses of Se98–xAg2Inx (x = 0, 2, 4, 6) system. Measurements of thermal transport properties (i.e., thermal conductivity, κ, and thermal diffusivity, χe) have been carried out using the transient plane source technique. Specific heat measurements have been done by differential scanning calorimetry. Thermomechanical properties (i.e., Vickers hardness, Hv, and modulus of elasticity, E) have been evaluated by the indenter test. The minimal energy for formation of microvoids, Eh, and microvoids volume, Vh, of the previously mentioned glassy system are discussed in terms of microhardness, Hv. Temperature and frequency dependence of dielectric constant, ε1, and dielectric loss, ε2, for the same system were measured in the frequency (50 Hz – 1000 kHz) and temperature (303–338 K) range. The experimental results illustrate that the values of dielectric constant, ε1, and dielectric loss, ε2, are decreased with frequency and increased with temperature. The maximum barrier height, Wb, is calculated using the dielectric measurements according to the Guintini equation. The morphology and microstructural analysis of as-prepared alloys are confirmed by X-ray diffraction, scanning electron microscope, and transmission electron microscope.

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