scholarly journals Effect of Silica Size and Content on Superamphiphobic Properties of Silica-Fluoropolymer Core-Shell Coatings

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2864
Author(s):  
Jiyoung Lee ◽  
Ha Soo Hwang ◽  
Tien N. H. Lo ◽  
Won-Gun Koh ◽  
In Park
Keyword(s):  
Heat Treatment ◽  
Average Particle Size ◽  
Composite Layer ◽  
Hierarchical Structures ◽  
Spray Coating ◽  
Silica Content ◽  
Core Shell ◽  
Average Particle ◽  
The Core ◽  
Shell Particles

We present a facile approach to fabricate superamphiphobic surfaces by spray coating silica-fluoropolymer core-shell particles without substrate pretreatment with an additional binder resin. A series of SiO2@poly(1H,1H,2H,2H-heptadecafluorodecyl methacrylate) (SiO2@PFMA) core-shell particles with core particles of different sizes were prepared via thiol-lactam initiated radical polymerization (TLIRP). The surface of each SiO2 particle with an average particle size of 12, 80, 150, and 350 nm was modified with (3-mercaptopropyl) trimethoxysilane and used as a seed for TLIRP. The SiO2@PFMA particles with various SiO2 sizes and contents were coated on aluminum substrates by a spray gun and then thermally treated to form a stable, rough composite layer. During the spray coating, the core-shell particles were aggregated by rapid evaporation of the solvent and then irregularly adhered to the substrate resulting in hierarchical structures. In the case of SiO2@PFMAs with low SiO2 contents, the roughness created mainly by the polymer shell disappeared during heat treatment. However, the substrates coated with SiO2@PFMAs with high SiO2 contents maintained the roughness even after heat treatment. The core-shell particles prepared with 12 nm SiO2 formed a stable superamphiphobic surface. The water/hexadecane contact and sliding angles on an aluminum plate coated with SiO2@PFMA, prepared using 12 nm silica at 46 wt% silica content (12 nm-SiO2(46)@PFMA), were 178.5°/159.2° and 1°/7°, respectively. The cross-cut tape test showed that adhesion between the 12nm-SiO2(46)@PFMA and the aluminum substrate was classified as 5B. A glass surface spray-coated with the core-shell composite particles exhibited transparent superhydrophobicity and translucent superamphiphobicity by controlling the concentration of the coating solution.

Synthesis and Characterization of Co3O4-MnxCo3-xO4 Core-Shell Nanoparticles

MRS Advances ◽  
2018 ◽  
Vol 3 (47-48) ◽  
pp. 2899-2904
Author(s):  
Ning Bian ◽  
Robert A. Mayanovic ◽  
Mourad Benamara
Keyword(s):  
Electron Microscopy ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Blocking Temperature ◽  
Core Shell ◽  
Average Particle ◽  
Shell Nanoparticles ◽  
X Ray ◽  
The Core ◽  
Core Shell Nanoparticles

ABSTRACTThe mixed-valence oxide Co3O4 nanoparticles, having the normal spinel structure, possess large surface area, active-site surface adsorption properties, and fast ion diffusivities. Consequently, they are widely used in lithium-ion batteries, as well as for gas sensing and heterogeneous catalysis applications. In our research, we use a two-step method to synthesize Co3O4–based core-shell nanoparticles (CSNs). Cobalt oxide (Co3O4) nanoparticles were successfully synthesized using a wet synthesis method employing KOH and cobalt acetate. Manganese was incorporated into the Co3O4 structure to synthesize inverted Co3O4@MnxCo3-xO4 CSNs using a hydrothermal method. By adjustment of pH value, we obtained two different morphologies of CSNs, one resulting in pseudo-spherical and octahedron-shaped nanoparticles (PS type) whereas the second type predominantly have a nanoplate (NP type) morphology. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and x-ray photoelectron spectroscopy (XPS) have been performed in order to determine the morphological and structural properties of our CSNs, whereas the magnetic properties have been characterized using a superconducting quantum interference device (SQUID) magnetometer. XRD and TEM results show that the CSNs have the same spinel crystal structure throughout the core and shell with an average particle size of ∼19.8 nm. Our Co3O4 nanoparticles, as measured prior to CSN formation, are shown to be antiferromagnetic (AFM) in nature as shown by the magnetization data. Our SQUID data indicate that the core-shell nanoparticles have both AFM (due to the Co3O4 core) and ferrimagnetic properties (of the shell) with a coercivity field of 300 Oe and 150 Oe at 5 K for the PS and NP samples, respectively. The magnetization vs temperature data show a spin order-disorder transition at ∼33 K and a superparamagnetic blocking temperature of ∼90 K for both batches.

scholarly journals TO/TMMP-TMTGE Double-Healing Composite Containing a Transesterification Reversible Matrix and Tung Oil-Loaded Microcapsules for Active Self-Healing

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1127 ◽  
Author(s):  
Nan Zheng ◽  
Jie Liu ◽  
Wenge Li
Keyword(s):  
Particle Size ◽  
Click Reaction ◽  
Average Particle Size ◽  
Core Shell ◽  
Average Particle ◽  
Self Healing ◽  
Tung Oil ◽  
The Core ◽  
Core Content ◽  
Healing System

Thermoset epoxies are widely used due to their excellent properties, but conventional epoxies require a complicated and time-consuming curing process, and they cannot self-healed, which limits their applications in self-healing materials. Extrinsic and intrinsic self-healing materials are applied in various fields due to their respective characteristics, but there is a lack of comparison between the two types of healing systems. Based on this, a thiol-epoxide click reaction catalyzed by an organic base was introduced to achieve the efficient preparation of thiol-epoxy. Furthermore, tung oil (TO)-loaded microcapsules were introduced into the thiol-epoxy matrix of dynamic transesterification to obtain a TO/TMMP-TMTGE self-healing composite with an intrinsic–extrinsic double-healing system. For comparison, a TMMP-TMTGE self-healing material with an intrinsic healing system was also prepared, which contained only thiol and epoxy curing chemistries. The effect of the core/shell ratio on the morphology, average particle size, and core content of TO-loaded microcapsules was studied. It was found that when the core/shell ratio was 3:1, the average particle size of the microcapsules was about 99.8 μm, and the microcapsules showed good monodispersity, as well as a core content of about 58.91%. The differential scanning calorimetry (DSC) results showed that the TO core was successfully encapsulated and remained effective after encapsulation. Furthermore, scanning electron microscopy (SEM), atomic force microscopy (AFM), tensile tests, and electrochemical tests were carried out for the two types of self-healing materials. The results showed that the TO/TMMP-TMTGE composite and TMMP-TMTGE material both had self-healing properties. In addition, the TO/TMMP-TMTGE composite was superior to the TMMP-TMTGE material due to its better self-healing performance, mechanical strength, and corrosion protection performance.

Synthesis of Crosslinkable Core-Shell Emulsion and Rheology of the Core-Shell/Amine Crosslinking Process

2009 ◽  
Vol 79-82 ◽  
pp. 2203-2206
Author(s):  
Jia Lu ◽  
Allan J. Easteal ◽  
Debes Bhattacharyya ◽  
Clive J. Bolt ◽  
Neil R. Edmonds
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Complex Viscosity ◽  
Shell Morphology ◽  
Core Shell ◽  
Average Particle ◽  
Crosslinking Reaction ◽  
Shear Moduli ◽  
The Core ◽  
Wide Range

Starve feed and semi-continuous seed emulsion polymerization were used to control the morphology of core shell latex particles with a vinyl acetate (VAc)/vinyl ester of versatic acid 10(VeoVa10) copolymer core surrounded by a poly(glycidyl methacrylate) (PGMA) shell. Pure core and core-shell structures were confirmed by TEM. The results suggest that core-shell morphology of the two stage emulsion was favoured by higher concentration of emulsifier in the seed latex: the particle size distribution of core-shell latex was broader than that of the core latex, and the average particle size of core-shell latex was larger than that of the core latex. The core-shell structure was not produced using seed emulsion with emulsifier concentration at or below the critical micelle concentration. The core shell emulsion containing epoxy functional group with added ethylene diamine showed an abrupt increase in dynamic shear moduli, G' and G'' and complex viscosity η* (several orders of magnitude) at about 35oC, during temperature ramps, over a wide range of angular frequencies. The time ramps showed that the crosslinking reaction did not occur at 15oC for the core-shell emulsion/amine system. The time for gel formation decreased with increase in temperature.

Magnetic Properties of Fe3O4/CoFe2O4 Composite Nanoparticles with Core/Shell Architecture

2020 ◽  
Vol 65 (10) ◽  
pp. 904
Author(s):  
V. O. Zamorskyi ◽  
Ya. M. Lytvynenko ◽  
A. M. Pogorily ◽  
A. I. Tovstolytkin ◽  
S. O. Solopan ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Spinel Ferrite ◽  
Composite Nanoparticles ◽  
Core Shell ◽  
Cofe2o4 Nanoparticles ◽  
Core Diameter ◽  
The Core ◽  
Shell Particles ◽  
Interface Parameters ◽  
Shell Composite

Magnetic properties of the sets of Fe3O4(core)/CoFe2O4(shell) composite nanoparticles with a core diameter of about 6.3 nm and various shell thicknesses (0, 1.0, and 2.5 nm), as well as the mixtures of Fe3O4 and CoFe2O4 nanoparticles taken in the ratios corresponding to the core/shell material contents in the former case, have been studied. The results of magnetic research showed that the coating of magnetic nanoparticles with a shell gives rise to the appearance of two simultaneous effects: the modification of the core/shell interface parameters and the parameter change in both the nanoparticle’s core and shell themselves. As a result, the core/shell particles acquire new characteristics that are inherent neither to Fe3O4 nor to CoFe2O4. The obtained results open the way to the optimization and adaptation of the parameters of the core/shell spinel-ferrite-based nanoparticles for their application in various technological and biomedical domains.

Fe@C core–shell and Fe@C yolk–shell particles for effective removal of 4-chlorophenol

2015 ◽  
Vol 3 (7) ◽  
pp. 3988-3994 ◽  
Author(s):  
Xiang Li ◽  
Fangyuan Gai ◽  
Buyuan Guan ◽  
Ye Zhang ◽  
Yunling Liu ◽  
...  
Keyword(s):  
Carbon Shell ◽  
Core Shell ◽  
The Core ◽  
Effective Removal ◽  
Shell Particles

Fe@C yolk–shell particles were synthesized by reducing the core with its own carbon shell to achieve the effective removal of 4-chlorophenol from water.

Effect of glycidyl methacrylate (GMA) on the stability of acrylic latex

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Guangfeng Wu ◽  
Yue Tao ◽  
Hong Kang ◽  
Huixuan Zhang
Keyword(s):  
Experimental Data ◽  
Glycidyl Methacrylate ◽  
Sodium Dodecyl ◽  
The Other ◽  
Lower Amount ◽  
Core Shell ◽  
Acrylic Latex ◽  
The Core ◽  
Shell Particles ◽  
The Stability

AbstractThe stability of core-shell particles (CSPs) with butyl acrylate (BA) as the core and methyl methacrylate (MMA)/glycidyl methacrylate (GMA) mixture in various compositions as the shell was investigated by turbidity measurements. The experiments demonstrate that lower amount addition of GMA could not improve the latex stability. When the amount of GMA exceeded 2% of the total reactants, it began to improve the stability of the latex. With the increasing content of GMA, the latex became more and more stable. On the other hand, experimental data also show that the stability was improved by increasing the concentration of sodium dodecyl sulfate (SDS).

The Preparation of Core/Shell Particles with Siloxane in the Shell

2005 ◽  
Vol 13 (7) ◽  
pp. 721-726
Author(s):  
Shunsheng Cao ◽  
Xiaobo Deng ◽  
Bailing Liu
Keyword(s):  
Dispersion Medium ◽  
Average Diameter ◽  
Butyl Methacrylate ◽  
Core Shell ◽  
The Core ◽  
Transmission Electron ◽  
Seeding Method ◽  
Emulsion Polymerisation ◽  
Shell Particles ◽  
Methacryloxypropyl Trimethoxysilane

Core-shell microspheres ranging in average diameter from 12.829 to 15.039 μm, with a poly butyl methacrylate (BMA) core, and a poly 3-(methacryloxypropyl)-trimethoxysilane (MATS) shell, were prepared with methanol as the dispersion medium, by a successive seeding method under kinetically controlled conditions. To date, although some of particles (PSi/PA) have been prepared by seeded emulsion polymerisation, only a few core/shell (PA/PSi) microspheres have been reported the literatures. To prepare core/shell (PA/PSi), the core was first synthesized by dispersion polymerisation and to form seeds; addition of MATS monomer was started after 90~95% conversion of the BMA. The reaction was prolonged for another 12 h to achieve complete consumption of MATS monomer. Microspheres; containing hydrophilic PBMA as the core and hydrophobic PMATS as the shell, were successfully formed through the free radical of surface in the core. The particles morphology and size distribution were examined using a Transmission electron microscope and a Malvern Master Sizer/E particle size analyser, respectively.

Influence of Various Reaction Parameters on the Process for Preparation of SiO2/TiO2 Core-Shell Particles

2015 ◽  
Vol 33 ◽  
pp. 27-37 ◽  
Author(s):  
Jhin Hong You ◽  
Yi Yin Kuo ◽  
Keh Ying Hsu
Keyword(s):  
Inorganic Compounds ◽  
Sol Gel ◽  
Chelating Agent ◽  
Condensation Process ◽  
Infrared Analysis ◽  
Ionic Surfactant ◽  
Core Shell ◽  
Reaction Parameters ◽  
The Core ◽  
Shell Particles

This study aims to describe the preparation and characterization of SiO2/TiO2 core-shell particles. In order to prepare the homogenous SiO2/TiO2 inorganic compounds by sol-gel process, SiO2 particles were used as the core, AcAc served as a chelating agent to chelate with TTIP (which was used as the precursor to TiO2), and PEG was added to stabilize the hydrolysis/condensation process. In addition, the ionic surfactant (SDS) and the nonionic surfactant (PVP) dispersed the core-shell particles. In order to improve the crystal structure, a high temperature was used to calcine the core-shell particles. The influence of various reaction parameters on the size, morphology and composition of the particles was also investigated. The properties of the particles were analyzed by electron microscopy, fourier transform infrared analysis, thermogravimetric analysis and powder X-ray diffraction.

Preparation and Characterization of Core-Shell Latex Containing PDMS in the Shell

e-Polymers ◽  
2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Baotan Zhang ◽  
Bailing Liu ◽  
Shunsheng Cao ◽  
Xiaobo Deng
Keyword(s):  
Photoelectron Spectroscopy ◽  
Hydrophobic Surface ◽  
Water Repellency ◽  
Atomic Ratio ◽  
Core Shell ◽  
Seeded Emulsion Polymerization ◽  
The Core ◽  
Static Contact ◽  
Ft Ir ◽  
Shell Particles

AbstractIn this paper, the composite latex particles with a polyacrylate (PA) core and a polydimethylsiloxane (PDMS) shell via 3-(methacryloxypropyl)- trimethoxy silane (MPS) as the medium to link the core and shell were prepared by semicontinuous seeded emulsion polymerization and were characterized by transmission electron microscopy (TEM), FT-IR, particle size analyzer and X-ray photoelectron spectroscopy (XPS). The TEM images indicated that the particles containing organic siloxane (D-40) displayed an evident core/shell structure. Additionally, the study by FT-IR and XPS also revealed that D4 could be grafted onto the surface of polyacrylate core because there appeared the characteristic peaks of Si-O-Si group and Si 2s and Si 2p in the spectra of FT-IR and XPS respectively. Besides, the atomic ratio of C/Si on the surface of the core/shell particles (D-40) was close to the ratio of C/Si in the latex of pure PDMS that could prove the PA particles were fully covered by PDMS and the properties of PDMS should be embodied in a maximal level. In order to testify the result, the surface properties of the films produced from the core/shell particles were also investigated by the static contact angle method. Compared with the copolymer of PA, the core/shell particles were more effective to create hydrophobic surface, so, the introduction of D4 was capable of obvious increase in water repellency.

Effect of Core/Shell Ratio on Performance of Paraffin/Polyurea Phase Change Microencapsules

2014 ◽  
Vol 556-562 ◽  
pp. 32-35 ◽  
Author(s):  
Wu Sheng Luo ◽  
Sheng Fei Yu ◽  
Jie Min Zhou
Keyword(s):  
Particle Size ◽  
Phase Change ◽  
Interfacial Polymerization ◽  
Average Particle Size ◽  
Energy Performance ◽  
Toluene Diisocyanate ◽  
Core Shell ◽  
Average Particle ◽  
Mass Ratio ◽  
Solid Liquid

In this paper, paraffin/polyurea (PU) phase change microencapsules were prepared through an interfacial polymerization method using composite paraffin with solid/liquid mass ratio 3:7 as core materials, 2,4 toluene diisocyanate (TDI) and ethylenediamine (EDA) as monomers, NP-10 as an emulsifier. It was explored the effect of the monomer mass ratio mEDA: mTDIon the yield of hollow PU microcapsules, and the effect of core/shell ratio on the particle size and coating efficiency and storage-energy performance of paraffin/PU phase change microencapsules. The experimental results showed the PU yield is increasing with the increasing of EDA:TDI mass ratio until 0.5:1,then keeps the constant. Paraffin/PU phase change microencapsules prepared with the core-shell ratio of 2:1 have better performance: the melting point of 28.1°C, the enthalpy of 58.4KJ/Kg, encapsulation efficiency of 87.5%, the average particle size of 4.32μm, and the uniform particle size distribution.

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