Synthesis and microstructure of conformal coatings on particulates

1997 ◽  
Vol 501 ◽  
Author(s):  
K. Rajan ◽  
P. Sajgalik ◽  
R. K. Singh ◽  
D. Kumar ◽  
J. Fitz-Gerald

ABSTRACTIn this paper we present an overview of two very different approaches to the synthesis of composite particulates which result in a “core-shell” type structure. It is shown that both these synthesis approaches result in very characteristic interface structures between the outer coating and the host particles. One synthesis strategy is to use laser ablation deposition on individual particles and the other is to “coat” particles ‘in-situ’ by taking advantage of solid state diffusional transformations. Examination of the interface between the outer shell and the core of the particle shows that textured or toptactical growth occurs and it is suggested that this unique crystallographic characteristic may be responsible for the properties offered by these engineered particulates. The applications of such engineered particulates is also discussed.

Author(s):  
J. T. Cunningham

On May 4th of the current year a number of small Pleuronectids were captured by the hand in a pool left by the ebb tide at Plymouth Breakwater, and brought to me alive. Two of them were very transparent, and, from their habit of lying on the right side when at rest, evidently sinistral forms. One of them was almost perfectly symmetrical; while in the other the torsion of the facial region and eyes had commenced. The pigmentation had the form of interrupted transverse bands, which were most conspicuous on the dorsal and ventral fins; on the dorsal fin seven bands were indicated. The terminal portion of the original trunk, containing the notochord, was seen at the upper edge of the caudal fin. The neurochord was covered with pigment, forming a very distinct band, situated, however, not in the skin, but in the connective tissue surrounding the neurochord or spinal cord. The mouth was large, and the snout upturned. The pectoral fin was large, the pelvic small. But the most important characteristic was the presence of two straight spines projecting laterally from the auditory region. These have been called otocystic spines by Prof. McIntosh, but I think they would be more appropriately described as periotic spines, as they are evidently projections of the periotic cartilage or bone; to which particular bones of the periotic region they belong has not been determined. Mr. Holt cut sections of the spines in situ, and found that they consisted of a knob of periotic cartilage passing into a mass of undifferentiated cells, the whole forming the core of a dermal spine consisting of hyaline ossified tissue. In my specimens I observed a third spine, much smaller, situated in the region of the frontal bone, behind and above the eye; it was visible in both the stages.


e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Guangfeng Wu ◽  
Yue Tao ◽  
Hong Kang ◽  
Huixuan Zhang

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).


2011 ◽  
Vol 90-93 ◽  
pp. 1702-1705
Author(s):  
Xi Zhang ◽  
Gang Xiang

We demonstrate the design of the recyclable photocatalyst based on ferromagnetic (FM) ZnO- TiO2 core-shell nanowires (NWs). Since the band gaps and band edge energies of bulk ZnO and anatase TiO2 are equal to each other within about 45mV, TiO2 and ZnO can form an p-p+ heterojunction free of band discontinuities and with a built-in potential. The resulting radial field will increase hole density in the TiO2 layer while reduce hole concentration at the interface between the core and the shell, which in turn will decrease the rate of recombination in the photocatalytic TiO2, and hence increase the efficiency of photocatalyst. On the other hand, the NWs with FM cores can be easily collected and refreshed using solenoid and suitable for the recyclable usage of the NW catalyst


2010 ◽  
Vol 168-170 ◽  
pp. 1833-1836
Author(s):  
Gang Qiang Geng ◽  
Jing Tao Guo ◽  
Jun Jun Zou ◽  
Gong Xun Bian

In order to obtain super aerogels heat insulating composite materials with silane coupling agent on the in-situ surface treatment. The core-shell structure composite materials have been prepared by dispersion polymerization process of polystyrene grafted on the SiO2 particles. By TEM on these samples the impact of the system components initiator polymerization parameters and dispersion process was discussed. The results showed that the system component of the greatest impact on conversion rate is the ratio of aerogels /St ,the optimum reaction temperature is 75 °C.With organic initiator KPS as initiator after a unique ultrasound technique to obtain the core-shell composite materials structure which coating is 70%.


2021 ◽  
Vol 22 (23) ◽  
pp. 12669
Author(s):  
Yi-Jen Huang ◽  
Yi-Fan Chen ◽  
Po-Han Hsiao ◽  
Tu-Ngoc Lam ◽  
Wen-Ching Ko ◽  
...  

Coaxial core/shell electrospun nanofibers consisting of ferroelectric P(VDF-TrFE) and relaxor ferroelectric P(VDF-TrFE-CTFE) are tailor-made with hierarchical structures to modulate their mechanical properties with respect to their constituents. Compared with two single and the other coaxial membranes prepared in the research, the core/shell-TrFE/CTFE membrane shows a more prominent mechanical anisotropy between revolving direction (RD) and cross direction (CD) associated with improved resistance to tensile stress for the crystallite phase stability and good strength-ductility balance. This is due to the better degree of core/shell-TrFE-CTFE nanofiber alignment and the crystalline/amorphous ratio. The coupling between terpolymer P(VDF-TrFE-CTFE) and copolymer P(VDF-TrFE) is responsible for phase stabilization, comparing the core/shell-TrFE/CTFE with the pristine terpolymer. Moreover, an impressive collective deformation mechanism of a two-length scale in the core/shell composite structure is found. We apply in-situ synchrotron X-ray to resolve the two-length scale simultaneously by using the small-angle X-ray scattering to characterize the nanofibers and the wide-angle X-ray diffraction to identify the phase transformations. Our findings may serve as guidelines for the fabrication of the electrospun nanofibers used as membranes-based electroactive polymers.


2011 ◽  
Vol 233-235 ◽  
pp. 2125-2128
Author(s):  
Li Li Xu ◽  
Sheng Peng Liu ◽  
Xuan Li

In this paper, vinylated magnesium hydroxide (MH) nanosheets were prepared with 3-(trimethoxysilyl) propyl methacrylate (γ-MPS) and pristine MH nanosheets, then the MH/polymer hybrid nanoparticles were prepared by in-situ emulsion copolymerization of vinylated MH nanosheets and styrene (St) monomer and styrene/butyl acrylate (St/BA) comonomer. The morphology, thermal stability and chemical structure of the final products were investigated in detail with transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and Fourier-transform infrared spectra (FTIR). The TEM results showed that the core-shell structure of MH/Polymer nanoparticles with MH-cores and Polymer-shell was formed.


1994 ◽  
Vol 127 (1) ◽  
pp. 173-185 ◽  
Author(s):  
S Takeda ◽  
S Okabe ◽  
T Funakoshi ◽  
N Hirokawa

Neurofilaments (NFs) are composed of triplet proteins, NF-H, NF-M, and NF-L. To understand the dynamics of NFs in vivo, we studied the dynamics of NF-H and compared them to those of NF-L, using the combination of microinjection technique and fluorescence recovery after photobleaching. In the case of NF-L protein, the bleached zone gradually restored its fluorescence intensity with a recovery half time of approximately 35 min. On the other hand, recovery of the bleached zone of NF-H was considerably faster, taking place in approximately 19 min. However, in both cases the bleached zone was stationary. Thus, it was suggested that NF-H is the dynamic component of the NF array and is interchangeable, but that it assembles with the other neurofilament triplet proteins in a more exchangeable way, implying that the location of NF-H is in the periphery of the core NF array mainly composed of NF-L subunits. Immunoelectron microscopy investigations of the incorporation sites of NF-H labeled with biotin compounds also revealed the lateral insertion of NF-H subunits into the preexisting NF array, taking after the pattern seen in the case of NF-L. In summary, our results demonstrate that the dynamics of the L and H subunit proteins in situ are quite different from each other, suggesting different and separated mechanisms or structural specialization underlying the behavior of the two proteins.


Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 859
Author(s):  
Nadezhda S. Smirnova ◽  
Evgeny V. Khramov ◽  
Galina N. Baeva ◽  
Pavel V. Markov ◽  
Andrey V. Bukhtiyarov ◽  
...  

A series of oxidative treatments of PdIn-supported intermetallic nanoparticles at different temperatures were performed. The bulk and surface structure of catalyst during phase transformation was investigated by bulk- and surface-sensitive techniques (in situ XAFS, DRIFTS of adsorbed CO). It was found that comparison of palladium and indium fractions in bulk and on the surface suggests the formation of a «core-shell» structure. According to obtained results, the core consists of In-depleted intermetallic compound or inhomogeneous bimetallic phase with the inner core of metallic Pd, when a mixture of indium oxide, metallic palladium and small part of PdIn is present on the surface.


2020 ◽  
Vol 12 (9) ◽  
pp. 10332-10340
Author(s):  
Xiaohui Li ◽  
Xing Zhou ◽  
Long Li ◽  
Danyang Zhao ◽  
Xinling Gong ◽  
...  

CrystEngComm ◽  
2020 ◽  
Vol 22 (5) ◽  
pp. 945-954 ◽  
Author(s):  
Lanjian Xu ◽  
Yangyang Yuan ◽  
Jie Zhang ◽  
Yanfei Zhang ◽  
Xiaomin Zhang ◽  
...  

A green and efficient steam-assisted crystallization (SAC) strategy was employed to synthesize a core–shell zeolite with different frameworks between the core and shell, Beta@Silicalite-1.


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