scholarly journals The Ophthalmic Performance of Hydrogel Contact Lenses Loaded with Silicone Nanoparticles

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1128 ◽  
Author(s):  
Nguyen-Phuong-Dung Tran ◽  
Ming-Chien Yang
Keyword(s):  
Electron Microscope ◽  
Oxygen Permeability ◽  
Contact Lenses ◽  
Sol Gel ◽  
Average Diameter ◽  
Tetraethyl Orthosilicate ◽  
Equilibrium Water Content ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Scanning Electron

In this study, silicone nanoparticles (SiNPs) were prepared from polydimethylsiloxane (PDMS) and tetraethyl orthosilicate (TEOS) via the sol-gel process. The resultant SiNPs were characterized by dynamic light scattering (DLS), transmission electron microscope (TEM), and scanning electron microscope (SEM). These SiNPs were then blended with 2-hydroxyethylmethacrylate (HEMA) and 1-vinyl-2-pyrrolidinone (NVP) before polymerizing into hydrogel contact lenses. All hydrogels were subject to characterization, including equilibrium water content (EWC), contact angle, and oxygen permeability (Dk). The average diameter of SiNPs was 330 nm. The results indicated that, with the increase of SiNPs content, the oxygen permeability increased, while the EWC was affected insignificantly. The maximum oxygen permeability attained was 71 barrer for HEMA-NVP lens containing 1.2 wt% of SiNPs with an EWC of 73%. These results demonstrate that by loading a small amount of SiNPs, the Dk of conventional hydrogel lenses can be improved greatly. This approach would be a new method to produce oxygen-permeable contact lenses.

Synthesis and Thermal Stability of Nontransformable Tetragonal (ZrO2)0.96(REO1.5)0.04 (Re=Sc3+, Y3+) Nanocrystals

2013 ◽  
Vol 334-335 ◽  
pp. 60-64 ◽  
Author(s):  
Mohammad Reza Loghman-Estark ◽  
Reza Shoja Razavi ◽  
Hossein Edris
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Scanning Electron Microscopy ◽  
Sol Gel ◽  
Average Diameter ◽  
X Ray ◽  
Transmission Electron ◽  
20 Nm ◽  
Thermal Stability Of ◽  
Scanning Electron

Scandia, yttria doped zirconia ((ZrO2)0.96(REO1.5)0.04(RE=Sc3+, Y3+)) nanoparticles were prepared by the modified sol-gel method. The microstructure of the products was characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. Thermal stabillity of SYSZ nanocrystals were also investigated. The SYSZ nanocrystals synthesized with EGM:Zr+4mole ratio 4:1, calcined at 700°C, have average diameter of ~20 nm.

Investigation on Nano-Sized ZnO Powder Doped with Al3+ Prepared by Sol-Gel Method

2012 ◽  
Vol 621 ◽  
pp. 3-7
Author(s):  
Yu Xiong ◽  
Ji Zheng ◽  
Song Lin Li ◽  
Xue Jia Liu ◽  
Lu Liang
Keyword(s):  
Electron Microscope ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nano Powder ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Doped Zno ◽  
Zno Powder ◽  
Tin Tetrachloride

Al3+-doped ZnO nano-powder was prepared by sol-gel process, using tin tetrachloride and titanium tetrachloride as starting materials. The crystallinity and purity of the powder were analyzed by X-ray diffraction spectrometer (XRD). And the size and distribution of Al3+-doped ZnO grains were studied using transmission electron microscope (TEM) and scanning electron microscope (SEM). The results showed that the Al3+ was successfully doped into the crystal lattice of tin oxide and that the electric conductivity of Al3+-doped ZnO sample was improved significantly.

Preparation of Alumina Powders through Pyrocatechol, Resorcinol Mediated Sol-Gel Method

2016 ◽  
Vol 850 ◽  
pp. 742-747
Author(s):  
Xiang Zhang ◽  
Ping Yun Li ◽  
Xiao De Guo ◽  
Ting Yan
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Sizes ◽  
Xrd Study ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Scanning Electron ◽  
Organic Monomer

Ultrafine alumina powders were synthesized through pyrocatechol and resorcinol mediated sol-gel process. Aluminum nitrate was applied as the Al source and PVP was the dispersant. X-ray diffraction (XRD) study displayed that γ-Al2O3 powders formed in the range of 800-900 °C, and then γ-Al2O3 transformed to α-Al2O3 at higher temperatures, pure α-Al2O3 powders could be obtained at 1000 °C by using resorcinol as organic monomer. The results of transmission electron microscopy (TEM) revealed that Al2O3 nanoparticles with γ crystalline phase had grain sizes in the range of 5-40 nm. Scanning electron microscopy (SEM) observation displayed that the morphology of the prepared α-Al2O3 powders had aggregated bodies formed by Al2O3 grains in the range of 0.2-0.5μm. These results provide a new way of preparation of alumina powders.

scholarly journals Hybrid Porous Microparticles Based on a Single Organosilica Cyclophosphazene Precursor

2020 ◽  
Vol 21 (22) ◽  
pp. 8552
Author(s):  
Vanessa Poscher ◽  
George S. Pappas ◽  
Oliver Brüggemann ◽  
Ian Teasdale ◽  
Yolanda Salinas
Keyword(s):  
Structural Control ◽  
Unique Feature ◽  
Sol Gel ◽  
Tetraethyl Orthosilicate ◽  
Mesoporous Organosilica ◽  
Transmission Electron ◽  
Porous Microparticles ◽  
Sol Gel Process ◽  
Phosphorus Containing ◽  
Spherical Microparticles

Porous organosilica microparticles consisting of silane-derived cyclophosphazene bridges were synthesized by a surfactant-mediated sol-gel process. Starting from the substitution of hexachlorocyclotriphosphazene with allylamine, two different precursors were obtained by anchoring three or six alkoxysilane units, via a thiol-ene photoaddition reaction. In both cases, spherical, microparticles (size average of ca. 1000 nm) with large pores were obtained, confirmed by both, scanning and transmission electron microscopy. Particles synthesized using the partially functionalized precursor containing free vinyl groups were further functionalized with a thiol-containing molecule. While most other reported mesoporous organosilica particles are essentially hybrids with tetraethyl orthosilicate (TEOS), a unique feature of these particles is that structural control is achieved by exclusively using organosilane precursors. This allows an increase in the proportion of the co-components and could springboard these novel phosphorus-containing organosilica microparticles for different areas of technology.

scholarly journals Sintesis Nanokomposit Fe3O4/TiO2 Sebagai Fotokatalis yang Dapat Diambil Kembali Dalam Fotoreduksi Limbah Ion Perak(I)

WARTA AKAB ◽  
2021 ◽  
Vol 44 (2) ◽  
Author(s):  
Adya Rizky Pradipta ◽  
Riri Enriyani ◽  
Lintannisa Rahmatia ◽  
Andita Utami
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Electron Microscope ◽  
Diffuse Reflectance ◽  
Sol Gel ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Sintesis nanokomposit Fe3O4/TiO2 sebagai fotokatalis yang dapat diambil kembali dalam fotoreduksi limbah ion Ag(I) telah dilakukan. Sintesis diawali dengan sintesis magnetit (Fe3O4) melalui kopresipitasi dan sonikasi. Pelapisan TiO2 dilakukan dengan proses sol-gel dengan penambahan benih atau seed TiO2 degusa, dan diikuti perlakuan termal pada suhu 500 °C. Hasil sintesis dikarakterisasi dengan fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope-energy dispersive X-ray (SEM-EDX), vibrating sample magnetometer (VSM) dan diffuse reflectance-UV (DR-UV). Uji aktivitas fotokatalis nanokomposit Fe3O4/TiO2 dilakukan terhadap fotoreduksi ion Ag(I) dengan sistem batch dalam reaktor tertutup yang dilengkapi dengan lampu UV. Hasil penelitian menunjukkan bahwa nanokomposit Fe3O4/TiO2 memiliki kemampuan fotokatalitik yang baik. Nanokomposit Fe3O4/TiO2 memiliki kemampuan fotoreduksi lebih baik dibanding TiO2 tanpa modifikasi. Fotoreduksi ion Ag(I) 12,5 ppm berlangsung optimum pada pH 6 dan waktu reaksi 90 menit dengan hasil sebesar 98,6 %.

Morphology dependence of 1,2-diphenylethylenediamine-derived organogelator templates in solvents and their influence in the production of nanostructured silica

2011 ◽  
Vol 65 (4) ◽  
Author(s):  
Tae Kim ◽  
Euh Jeong ◽  
Chae Oh ◽  
Myung Hyun ◽  
Mee Lee ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Sol Gel ◽  
Outer Diameter ◽  
Transmission Electron ◽  
Tetraethoxy Silane ◽  
Inner Diameter ◽  
Nanostructured Silica ◽  
Scanning Electron ◽  
Made In

AbstractThe 1,2-diphenylethylenediamine-based neutral or cationic organogelator-templates, currently employed in the production of silica nanomaterials, were initially evaluated for their versatile gelation ability and found to be gelled in the majority of organic solvents tested. Scanning electron microscope and transmission electron microscope, images of neutral organogels made from different solvents revealed that they assembled into a plate-shaped, or rod-shaped morphology, respectively in ethanol or butan-1-ol and in acetonitrile or tetrahydrofurane. Similarly, a 1: 1 mixture (mass) of neutral and cationic gelators formed different morphologies in the solvents tested. Sol-gel polycondensation of tetraethoxy silane using either individual gels (neutral or cation) or a 1: 1 mixture of gels was explored. The experimental results and the scanning electron microscopy and transmission electron microscopy images revealed that silica nanotubes with an inner diameter of 82 nm and an outer diameter of 620 nm were obtained from the 1: 1 mixture of neutral and cationic gelator in ethanol, whereas silica nanoparticles were obtained using gels made in the other solvents tested.

Preparation of Silicon Dioxide Fiber via Sol-Gel Process

2008 ◽  
Vol 368-372 ◽  
pp. 794-796
Author(s):  
Xiao Hui Wang ◽  
Xiao Ping Liang ◽  
Shao Bo Xin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrochloric Acid ◽  
Silicon Dioxide ◽  
Sol Gel ◽  
Tetraethyl Orthosilicate ◽  
Molar Ratio ◽  
Sol Gel Process ◽  
Different Temperatures ◽  
Scanning Electron

Silicon dioxide gel fibers were prepared by hydrolysis reaction of tetraethyl orthosilicate (TEOS). TEOS was used as basic materials, anhydrous ethanol (EtOH) as solvent and hydrochloric acid (HCl) as the catalyst. The best proportion of the chosen materials (TEOS, EtOH, H2O and HCl) was 1:1:1.5:0.03(molar ratio).Gel fibers were investigated by thermogravimetry (TG). Silicon dioxide fibers were obtained by treating the gel fibers at different temperatures. The calcined fibers were characterized by scanning electron microscopy (SEM). The optimal sintering schedule was obtained. Silicon dioxide fiber dried at 200°C for 1 hour then calcined at 800°C for 3 hours was the best.

Evaluation Nanostructure Properties of Bioactive Glass Scaffolds for Bone Tissue Engineering

2013 ◽  
Vol 829 ◽  
pp. 289-293 ◽  
Author(s):  
Samaneh Izadi ◽  
Saeed Hesaraki ◽  
Masoud Hafezi-Ardakani
Keyword(s):  
Tissue Engineering ◽  
Compressive Strength ◽  
Electron Microscope ◽  
Bioactive Glass ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Glass Powder ◽  
Sol Gel ◽  
Transmission Electron ◽  
Scanning Electron

The use of biomaterials in bone tissue engineering newly has been developed. They are biocompatible material which are reabsorbed in body and replaced with newly formed tissue. Bioactive glass scaffolds will be appropriate candidates if pore morphology, size and structures are controlled. Scaffolds with nanostructure will provide these goals. In this research bioglass powder was synthesized with sol-gel method to achieve nanostructure powder. The glass powder was characterized with transmission electron microscope (TEM). Scaffolds were prepared with combination of bioglass powder and sugar as porogen followed by pressing at 80 MPa then sintering at 1050 oC. The morphology of sintered scaffolds was characterized with scanning electron microscope (SEM) and porosity was measured with density method. Mechanical properties were assessed with compressive strength. The TEM results show that synthesized powder has particle size about 25 nm. The SEM results show that nanopores and macropores are connectively distributed in whole part of scaffolds. The compressive strength of scaffolds was 0.8 MPa. Overall, the scaffold is suggested that is appropriate alternative for bone tissue engineering.

Application of Scanning Electron Microscopy to Medical Research

1969 ◽  
Vol 27 ◽  
pp. 12-13
Author(s):  
J. D. Hutchison
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Medical Research ◽  
Prosthetic Heart Valve ◽  
School Of Medicine ◽  
Transmission Electron ◽  
Definition Of ◽  
Mechanism Of Failure ◽  
The Brain ◽  
Scanning Electron

When the transmission electron microscope was commercially introduced a few years ago, it was heralded as one of the most significant aids to medical research of the century. It continues to occupy that niche; however, the scanning electron microscope is gaining rapidly in relative importance as it fills the gap between conventional optical microscopy and transmission electron microscopy.IBM Boulder is conducting three major programs in cooperation with the Colorado School of Medicine. These are the study of the mechanism of failure of the prosthetic heart valve, the study of the ultrastructure of lung tissue, and the definition of the function of the cilia of the ventricular ependyma of the brain.

Observability of Very Thick Specimen by Using Transmission Scanning Electron Microscope

1971 ◽  
Vol 29 ◽  
pp. 26-27
Author(s):  
K. Shibatomi ◽  
T. Yamanoto ◽  
H. Koike
Keyword(s):  
Electron Microscope ◽  
Image Quality ◽  
Scanning Electron Microscope ◽  
Chromatic Aberration ◽  
Image Contrast ◽  
Objective Lens ◽  
Thick Specimen ◽  
Transmission Electron ◽  
Scanning Electron

In the observation of a thick specimen by means of a transmission electron microscope, the intensity of electrons passing through the objective lens aperture is greatly reduced. So that the image is almost invisible. In addition to this fact, it have been reported that a chromatic aberration causes the deterioration of the image contrast rather than that of the resolution. The scanning electron microscope is, however, capable of electrically amplifying the signal of the decreasing intensity, and also free from a chromatic aberration so that the deterioration of the image contrast due to the aberration can be prevented. The electrical improvement of the image quality can be carried out by using the fascionating features of the SEM, that is, the amplification of a weak in-put signal forming the image and the descriminating action of the heigh level signal of the background. This paper reports some of the experimental results about the thickness dependence of the observability and quality of the image in the case of the transmission SEM.

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