Morphology control of silica/poly(methyl methacrylate-co-styrene) hybrid nanoparticles via multiple-miniemulsion approach

e-Polymers ◽  
2016 ◽  
Vol 16 (2) ◽  
pp. 91-98 ◽  
Author(s):  
Maryam Mohammadpour Nazarabady ◽  
Gholam Ali Farzi
Keyword(s):  
Early Stage ◽  
Sol Gel ◽  
Hybrid Nanoparticles ◽  
Transmission Electron Microscopy Micrographs ◽  
Polymer Hybrid ◽  
Droplet Nucleation ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Inverse Miniemulsion ◽  
Acid Catalyzed

AbstractAn appropriate approach has been used for the preparation of silica/P(MMA-co-St) hybrid nanoparticles through converting previously prepared inverse miniemulsions into a direct miniemulsion and consequently, using the droplet nucleation polymerization technique. In the early stage of the procedure, silica particles were synthesized from TEOS in the presence of NH4OH or HCl as a catalyst through a base or acid-catalyzed sol-gel process. TEOS, ethanol and tirmethoxyvinylsilan were mixed in MMA:St (50:50) to create the inverse miniemulsion I, similarly CTAB, NH4OH/HCl and distilled water were dispersed into MMA:St (50:50) and called inverse miniemulsion II. Then, the two mentioned inverse miniemulsions were emulsified in water to achieve direct miniemulsion. The nature of the catalyst and TEOS concentration varied, for the aims of investigation, their effect on the morphology and size of hybrid nanoparticles. This route provided a unique process for silica/polymer hybrid nanoparticles production, avoiding organic solvents. Transmission electron microscopy micrographs revealed that, the morphology of the hybrid nanoparticles can be controlled by the nature of the catalyst.

Hybrid Nanocomposites Based on Metal Oxides and Polysiloxanes with Controlled Morphology

2007 ◽  
Vol 1007 ◽  
Author(s):  
Sorin Ivanovici ◽  
Christoph Rill ◽  
Claudia Feldgitscher ◽  
Guido Kickelbick
Keyword(s):  
Metal Oxides ◽  
Sol Gel ◽  
Hybrid Nanocomposites ◽  
Hybrid Nanoparticles ◽  
Spectroscopic Methods ◽  
Metal Alkoxides ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Ft Ir ◽  
Controlled Morphology

ABSTRACTHybrid materials based on polysiloxanes and metal oxides (SiO2, TiO2, ZrO2) were prepared by hydrosilation of allyl acetoacetate (AAA) modified metal alkoxides (M(OR)4; M = Ti, Zr; R = ethyl, isopropyl) or vinyl triethoxysilane with poly(dimethylsiloxane-co-hydrosiloxane) (PDMS-co-PMHS). The obtained compounds acted as single-source precursors in the sol-gel process. Various spectroscopic methods showed the complete functionalization of the polysiloxane chains with the complexes. When alcohols were used as solvents in the sol-gel process, hybrid nanoparticles were obtained, as observed by dynamic light scattering (DLS) measurements, transmission electron microscopy (TEM), and spectroscopic methods such as NMR and FT-IR.

Texture Evaluation of Sol-Gel Derived Mesoporous Bioactive Glass

2013 ◽  
Vol 284-287 ◽  
pp. 230-234
Author(s):  
Yu Jen Chou ◽  
Chi Jen Shih ◽  
Shao Ju Shih
Keyword(s):  
Surface Area ◽  
Calcination Temperature ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Nitrogen Adsorption ◽  
Bioactive Glasses ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Adsorption Desorption

Recent years mesoporous bioactive glasses (MBGs) have become important biomaterials because of their high surface area and the superior bioactivity. Various studies have reported that when MBGs implanted in a human body, hydroxyl apatite layers, constituting the main inorganic components of human bones, will form on the MBG surfaces to increase the bioactivity. Therefore, MBGs have been widely applied in the fields of tissue regeneration and drug delivery. The sol-gel process has replaced the conventional glasses process for MBG synthesis because of the advantages of low contamination, chemical flexibility and lower calcination temperature. In the sol-gel process, several types of surfactants were mixed with MBG precursor solutions to generate micelle structures. Afterwards, these micelles decompose to form porous structures after calcination. Although calcination is significant for contamination, crystalline and surface area in MBG, to the best of the authors’ knowledge, only few systematic studies related to calcination were reported. This study correlated the calcination parameters and the microstructure of MBGs. Microstructure evaluation was characterized by transmission electron microscopy and nitrogen adsorption/desorption. The experimental results show that the surface area and the pore size of MBGs decreased with the increasing of the calcination temperature, and decreased dramatically at 800°C due to the formation of crystalline phases.

Low-Temperature Synthesis of Nano-Crystalline ZnTiO3 Powders by Aqueous Sol-Gel Process

2014 ◽  
Vol 543-547 ◽  
pp. 3741-3744
Author(s):  
Quan Jing Mei ◽  
Cong Ying Li ◽  
Jing Dong Guo ◽  
Gui Wang ◽  
Hai Tao Wu
Keyword(s):  
Sol Gel ◽  
Zinc Nitrate ◽  
X Ray Diffraction ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
Calcination Process ◽  
X Ray ◽  
Nano Crystalline ◽  
Transmission Electron ◽  
Sol Gel Process

The ecandrewsite-type ZnTiO3was successfully synthesized by the aqueous sol-gel method using TiO2dioxide and zinc nitrate as starting materials instead of expensive organic solvent and metal alkoxides. The as-prepared nanopowders were characterized by X-ray diffraction (XRD), differential thermal analysis (DTA) and transmission electron microscopy (TEM), respectively. The results showed that the calcination process of gel consisted of a series of oxidation and combustion reactions, accompanied by significantly exothermal effects. Highly reactive nanosized ZnTiO3powders were successfully obtained at 850 °C with particle size ~50 nm. By comparison, the aqueous sol-gel process was the most effective and least expensive technique used for the preparation of ZnTiO3nanopowders.

Characterization of Nanostructured Silica as Carrier for Insecticides Deltamethrin, Pyriproxyfen, and Chlorpyrifos and Testing the Insecticidal Efficacy Against Trogoderma granarium (Coleoptera: Dermestidae) Larvae

2019 ◽  
Vol 113 (1) ◽  
pp. 511-517
Author(s):  
Masumeh Ziaee ◽  
Asgar Babamir-Satehi
Keyword(s):  
Electron Microscopy ◽  
Silica Nanoparticles ◽  
Sol Gel ◽  
Sem Analysis ◽  
Efficient Treatment ◽  
Trogoderma Granarium ◽  
Transmission Electron ◽  
Insecticidal Efficacy ◽  
Sol Gel Process ◽  
Nanostructured Silica

Abstract Nanostructured silica can be used as a carrier of pesticides to enhance stability and controlled release of agrochemicals with an effective concentration on target pests. Silica nanoparticles (SNPs) were synthesized by sol–gel process and employed as a carrier of three different insecticides including deltamethrin, pyriproxyfen, and chlorpyrifos. The SNPs were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis and the insecticides-loaded in SNPs were characterized by transmission electron microscopy (TEM). The toxicity of insecticides alone and loaded in SNPs was evaluated against small and large larvae of Trogoderma granarium Everts on concrete surfaces. The immediate mortality was counted after 1, 3, and 7 d of exposure, and then surviving individuals were transferred to untreated surfaces for seven more days, with delayed mortality was recorded. Small larvae were more susceptible than large ones on all insecticide treatments. In addition, insecticides loaded in silica nanoparticles were more effective when compared with application of the insecticides alone. For immediate mortality, deltamethrin loaded in SNPs was the most efficient treatment causing 70.5% mortality on small and 55.5% mortality on large larvae after 7 d of exposure to the highest concentration. Pyriproxyfen loaded in SNPs caused low immediate mortality, but the mortality increased in delayed count indicated that the insecticide could control the larvae even after they have been removed from treated surfaces. It can be concluded that loading insecticides in SNPs could significantly increase their insecticidal efficiency, but this increase was compound-dependent.

Preparation of SiO2 Antireflective Film by a Base/Acid Two-Step Catalyzed Sol-Gel Process

2013 ◽  
Vol 860-863 ◽  
pp. 845-848 ◽  
Author(s):  
De Yi Li ◽  
Kun Peng ◽  
Ling Ping Zhou ◽  
Jia Jun Zhu
Keyword(s):  
Raw Materials ◽  
Salt Spray ◽  
Sol Gel ◽  
Acid Base ◽  
Gel Method ◽  
Antireflective Film ◽  
Sol Gel Process ◽  
Acid Catalyzed ◽  
Antireflective Films ◽  
Silica Sols

SiO2 antireflective films were prepared by two-step catalyzed sol-gel method with TEOS as the raw materials, acid and ammonia as catalyst. Effects of the ratio of acid-catalyzed and base-catalyzed silica sols on the transmittance and stability of SiO2 film were investigated. The transmittance can be adjusted by change the ratio of base-catalyzed sols, and a higher transmittance can be obtained in the higher ratio of base-catalyzed coatings. A higher stability of SiO2 film in salt spray can be obtained in higher ratio of acid-catalyzed AR coatings. AR coatings with excellent transmittance and stability can be obtained by adjusting the ratio of acid/base catalyzed silica sols.

Preparation of Silica/Polymer Hybrid Nanoparticles via a Semi-Continuous Soup-Free Emulsion Polymerization

2015 ◽  
Vol 1120-1121 ◽  
pp. 233-242
Author(s):  
Joshua Qing Song Li ◽  
Hai Wang ◽  
Yan Qiu Wang
Keyword(s):  
Emulsion Polymerization ◽  
Early Stage ◽  
Size Exclusion ◽  
Hybrid Nanoparticles ◽  
Core Shell ◽  
Particle Coagulation ◽  
Shell Nanoparticles ◽  
Sem Images ◽  
Spectra Analysis ◽  
Polymer Hybrid

Hybrid nanoparticles were prepared by direct polymerization of methyl methacrylate, vinyl acetate, and styrene monomers onto the unmodified hydrophilic surfaces of 33 nm silica nanoparticles in a semi-continuous soap-free emulsion polymerization at a monomer starved condition. The polymerization was initiated by potassium persulfate with constant monomer feed at 0.01, 0.02, or 0.04 mL/min. The growth of the core-shell nanoparticles were measured by a laser particle size analyzer. FT-IR spectra analysis confirmed the hybrid structures of the synthesized nanoparticles. SEM images and size exclusion chromatography (SEC) results indicated regular core-shell microsphere structures. The hybrid nanoparticles increased in monodispersity and size over 100 nm with the reaction. However, SiO2/polystyrene (PS) nanoparticles grew much faster compared with SiO2/polymethyl methacrylate (PMMA) and SiO2/polyvinyl acetate (PVAC). There was particle coagulation, about 12 SiO2/PS particles aggregating to one, in the early stage of the seeded process. In addition, PS secondary particles were formed before the particle coagulation, and then merged with the SiO2/PS nanoparticles in the particle coagulation. The formation of SiO2/polymer hybrid nanoparticles depended on the hydrophilic characteristics of the polymer, and the size of silica seeds.

Microfluidic Synthesis of Lipid-Polymer Hybrid Nanoparticles for Targeted Drug Delivery

MRS Advances ◽  
2016 ◽  
Vol 1 (29) ◽  
pp. 2155-2160
Author(s):  
Eri A. Takami ◽  
Folarin Erogbogbo
Keyword(s):  
Drug Delivery ◽  
Low Cost ◽  
Three Dimensional ◽  
Hybrid Nanoparticles ◽  
Dimensional Structure ◽  
Force Microscopy ◽  
Polymer Hybrid ◽  
Medical Issues ◽  
Transmission Electron ◽  
Size And Morphology

ABSTRACTLipid-polymer hybrid nanoparticles (LPHN) have great potential as drug delivery devices for treatment of serious medical issues such as cardiovascular disease, tuberculosis, and cancer. Nanoprecipitation is a commonly used method to synthesize LPHN in a low cost manner. However, this multi-step process proves to be difficult in consistently producing uniformly sized nanoparticles. Here we developed a microfluidic device that utilizes a three-channel pathway and mixer channel to synthesize uniformly sized LPHN in a controlled manner. Dynamic light scattering results of the microfluidic synthesized nanoparticles show decrease in diameter size from 140 nm to 40 nm as the Reynolds number of the channel inflow increases. Transmission electron microscopy confirms the size and morphology of the nanoparticles. Three dimensional structure of the LPHN were observed using atomic force microscopy. The production of higher quality nanoparticles using our microfluidics device can expedite the research and development process of drug delivering lipid polymer nanoparticles.

Synthesis and Characterization of SiO2@Y2MoO6:Eu3+ Core–Shell Structured Spherical Phosphors by Sol–Gel Process

2016 ◽  
Vol 16 (4) ◽  
pp. 3914-3920 ◽  
Author(s):  
G. Z Li ◽  
F. H Liu ◽  
Z. S Chu ◽  
D. M Wu ◽  
L. B Yang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Annealing Temperature ◽  
Uv Light ◽  
Sol Gel ◽  
Spherical Shape ◽  
Core Shell ◽  
X Ray ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Average Size

SiO2@Y2MoO6:Eu3+ core–shell phosphors were prepared by the sol–gel process. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectra (EDS), transmission electron microscopy (TEM), photoluminescence (PL) spectra as well as kinetic decays were used to characterize the resulting SiO2@Y2MoO6:Eu3+ core–shell phosphors. The XRD results demonstrated that the Y2MoO6:Eu3+ layers on the SiO2 spheres crystallized after being annealed at 700 °C and the crystallinity increased with raising the annealing temperature. The obtained core–shell phosphors have spherical shape with narrow size distribution (average size ca. 640 nm), non-agglomeration, and smooth surface. The thickness of the Y2MoO6:Eu3+ shells on the SiO2 cores could be easily tailored by varying the number of deposition cycles (70 nm for four deposition cycles). The Eu3+ shows a strong PL emission (dominated by 5D0–7F2 red emission at 614 nm) under the excitation of 347 nm UV light. The PL intensity of Eu3+ increases with increasing the annealing temperature and the number of coating cycles.

scholarly journals Fabrication of TiO2Nanotanks Embedded in a Nanoporous Alumina Template

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
C. Massard ◽  
S. Pairis ◽  
V. Raspal ◽  
Y. Sibaud ◽  
K. O. Awitor
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Thermal Treatments ◽  
X Ray Diffraction ◽  
Alumina Template ◽  
Nanoporous Alumina ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Sol Gel Process

The feasibility of surface nanopatterning with TiO2nanotanks embedded in a nanoporous alumina template was investigated. Self-assembled anodized aluminium oxide (AAO) template, in conjunction with sol gel process, was used to fabricate this nanocomposite object. Through hydrolysis and condensation of the titanium alkoxide, an inorganic TiO2gel was moulded within the nanopore cavities of the alumina template. The nanocomposite object underwent two thermal treatments to stabilize and crystallize the TiO2. The morphology of the nanocomposite object was characterized by Field Emission Scanning Electron Microscopy (FESEM). The TiO2nanotanks obtained have cylindrical shapes and are approximately 69 nm in diameter with a tank-to-tank distance of 26 nm. X-ray diffraction analyses performed by Transmission Electron Microscopy (TEM) with selected area electron diffraction (SAED) were used to investigate the TiO2structure. The optical properties were studied using UV-Vis spectroscopy.

Microstructural characteristics and photoluminescence performance of nanograined thermally treated CeO2-TiO2 xerogels

2007 ◽  
Vol 22 (5) ◽  
pp. 1182-1187
Author(s):  
Amita Verma ◽  
A.K. Srivastava ◽  
N. Karar ◽  
Harish Chander ◽  
S.A. Agnihotry
Keyword(s):  
Electron Microscopy ◽  
Crystallite Size ◽  
Sol Gel ◽  
Structural Features ◽  
X Ray Diffraction ◽  
Molar Ratios ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Crystallite Sizes ◽  
Thermally Treated

Nanostructured thermally treated xerogels have been synthesized using a sol-gel process involving cerium (Ce) chloride heptahydrate and titanium (Ti) propoxide mixed in different Ce:Ti molar ratios. Structural features of the xerogels have been correlated with their photoluminescence (PL) response. The crystallite sizes in the samples lie in the nanorange. The x-ray diffraction and transmission electron microscopy results have confirmed the coexistence of CeO2 and TiO2 nanocrystallites in these xerogels. In general, a decrease in the CeO2 crystallite size and an increase in the TiO2 crystallite size are observed in the xerogels as a function of Ti content. Scanning electron microscopy results have evidenced the evolution of ordered structure in the xerogels as a function of TiO2 content. Although both of the phases (CeO2 and TiO2) have exhibited PL in ultraviolet and visible regions, the major luminescence contribution has been made by the CeO2 phase. The largest sized CeO2 crystallites in 1:1 thermally treated xerogel have led to its highest PL response. PL emission in the xerogels is assigned to their nanocrystalline nature and oxygen vacancy-related defects.

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