Synthesis of Highly Photoluminescent CdTe Nanocrystals and Their Incorporation into Glass Matrices

2004 ◽  
Vol 829 ◽  
Author(s):  
Norio Murase ◽  
Chunliang Li
Keyword(s):  
Coupling Agent ◽  
Silane Coupling Agent ◽  
Thioglycolic Acid ◽  
Sol Gel ◽  
Molar Ratio ◽  
Amino Group ◽  
Cdte Nanocrystals ◽  
Silane Coupling ◽  
Glass Matrices ◽  
Luminescent Nanocrystals

ABSTRACTPhotoluminescence (PL) efficiency of thioglycolic-acid (TGA)-stabilized CdTe nanocrystals in water depends strongly on the amount of TGA upon synthesis. The less the amount, the higher the PL efficiency obtained if the colloid is not precipitated. When the molar ratio of TGA against Cd2+ upon preparation is ca. 1.3, PL efficiency of as-prepared solution becomes the maximum and exceeds 60% in red-emitting region. In this case, the spectral widths of the PL become the minimum. We have encapsulated these highly luminescent nanocrystals into glass matrices by using a sol-gel method. Silane coupling agent having an amino-group is effective to preserve the surface of the nanocrystals. The glass thus prepared is stable and shows PL efficiency as high as 40%.

The Preparation of Flexible Substrate Using BaTiO3/Polymer Composites for Application in High Frequency Devices

2012 ◽  
Vol 512-515 ◽  
pp. 1142-1145 ◽  
Author(s):  
Chien Min Cheng ◽  
Kai Huang Chen ◽  
Yuan Tai Hsieh ◽  
Fuh Cheng Jong
Keyword(s):  
Coupling Agent ◽  
Silane Coupling Agent ◽  
Flexible Substrate ◽  
Sol Gel ◽  
Ceramic Powder ◽  
Electrical Measurement ◽  
Organic Polymer ◽  
Physical Analysis ◽  
Silane Coupling ◽  
The Impact

BaTiO3/ which has good dielectric properties, they were widely used in ceramic capacitors, thermistors, etc. In this study, BaTiO3/ ceramics prepared by sol-gel powder, then mixed in the organic polymer polyether imide (PEI) and dispersant (surface active agents) and silane coupling agent (Silane Coupling Agent) of the composite material on flexible substrates, And analysis of its properties and electrical properties. Increase by a ceramic powder, to explore the impact of the substrate. In the physical analysis is used XRD, SEM to measure the intensity of crystalline phase and surface uniformity of the electrical measurement using HP4294 measuring dielectric constant and dielectric loss.

Design of Experiment: A Statistical Approach to Understanding Factors Influencing Surface Properties of Sol-Gel Based Non-Stick Ceramic Coatings

2012 ◽  
Vol 622-623 ◽  
pp. 420-425
Author(s):  
Alex Kwasi Kumi ◽  
Allan Chelashaw ◽  
Yu Mei Zhang ◽  
Li Feng Li
Keyword(s):  
Contact Angle ◽  
Surface Properties ◽  
Coupling Agent ◽  
Silane Coupling Agent ◽  
Sol Gel ◽  
Ceramic Coatings ◽  
Curing Temperature ◽  
Factors Influencing ◽  
Silane Coupling ◽  
Advancing Contact Angle

Ceramic coatings based on sol-gel method have increasingly gained much attention in recent times. In order to ascertain important experimental factors (variables) influencing surface properties, such as adhesion, pencil hardness and advancing contact angle (non-stick) of sol coatings, a 26-1-factorial screening design with six experimental variables, precursor mole ratio, low surface energy polymer concentration, silane coupling agent (SCA) concentration, silica nanoparticles concentration (SNP’s),curing temperature and three responses ( surface properties) were investigated. The results indicate that silane coupling agent concentration, SNP’s concentration and their interaction were the most significant experimental factors influencing advancing contact angle. None of the experimental factors studied were statistically significant with respect to hardness and adhesion.

Preparation and Modification of Nanometer TiO2 with High Reflectivity

2014 ◽  
Vol 1004-1005 ◽  
pp. 51-54
Author(s):  
Su Zhao ◽  
Sha Sha Liu ◽  
Yan Jun Guo ◽  
Wei Wei
Keyword(s):  
Titanium Dioxide ◽  
Coupling Agent ◽  
Silane Coupling Agent ◽  
Sol Gel ◽  
Reaction System ◽  
High Reflectivity ◽  
Titanium Dioxide Powder ◽  
Dioxide Powder ◽  
Silane Coupling ◽  
Nano Titanium Dioxide

In order to prepare high reflectivity titanium dioxide, by sol - gel method after nano-titanium dioxide powder, which silane coupling agent KH-570 covering it and make its surface modification.When the reaction temperature is 40 °C, drop accelerated rate 1.5mL/min, calcination temperature about 600 °C, got titanium dioxide with relatively high reflectivity and particle size in around 65 nm.When the amount of the silane coupling agent is 0.5%, the pH of reaction system is 6.5, and the reaction time was 1.5h, the nano-modified titanium dioxide particles with high reflectance.

Poly(amic acid) Treatment on BaTiO3 and Effect on the Dielectric Properties of BaTiO3/Polyimide Composites

2012 ◽  
Vol 560-561 ◽  
pp. 880-885
Author(s):  
Young Jun Ko ◽  
Soo Jung Kang ◽  
Hai Yan An ◽  
Jin Hwan Kim
Keyword(s):  
Hydrogen Peroxide ◽  
Dielectric Properties ◽  
Coupling Agent ◽  
Acid Treatment ◽  
Silane Coupling Agent ◽  
Amic Acid ◽  
Amino Group ◽  
Silane Coupling ◽  
Polyimide Composites

We first modify the surfaces of BaTiO3 by hydrogen peroxide to induce hydoxyl groups that will be further reacted with a coupling agent. Then, with a silane coupling agent, we induce the amino group on the surface of particles. Modified BaTiO3 particles with the PI precursor (poly(amic acid)) are able to obtain poly(amic acid)-wrapped BaTiO3 particles. By employing this approach, higher dielectric value is obtained for the composite comprised of PI and PAA-wrapped BaTiO3 particles.

Preparation and Modification of Nano- TiO2 Pigment for Coating

2010 ◽  
Vol 146-147 ◽  
pp. 1675-1680
Author(s):  
Xiao Hui Zhang ◽  
Qi Guang Cao ◽  
Lin Hu ◽  
Jian Yu Cui
Keyword(s):  
Titanium Dioxide ◽  
Coupling Agent ◽  
Silane Coupling Agent ◽  
Sol Gel ◽  
Raw Material ◽  
Tem Analysis ◽  
Titanium Dioxide Powder ◽  
Dioxide Powder ◽  
Silane Coupling ◽  
Nanoscale Titanium Dioxide

Nanoscale titanium dioxide powder were prepared in terms of sol-gel process with Ti(OC4H9) as raw material. TEM analysis show that the size of nanoparticle are between 50～ 100nm.The results of XRD test indicate that the crystal style of the product is rutile type. In order to apply nanoscale titanium dioxide to coating as pigment, the nanoscale particles were modified in terms of esterifying reaction,silane coupling agent and organic titanate coupling agent. The results of contact angle test show that the oleophilic of modified product with organic titanate coupling agent is stronger than that with silane coupling agent and esterifying reaction.

Compatibility Enhancement of Polyimide–Silica Hybrid Sol–Gel Materials Without Incorporation of Silane-Coupling Agent

2011 ◽  
Vol 11 (4) ◽  
pp. 3454-3463
Author(s):  
Wei-I Hung ◽  
Chang-Jian Weng ◽  
Kuan-Yeh Huang ◽  
Pei-Shan Wu ◽  
Jiun-Kuang Dai ◽  
...  
Keyword(s):  
Coupling Agent ◽  
Silane Coupling Agent ◽  
Sol Gel ◽  
Silane Coupling ◽  
Silica Hybrid

Preparation of Nano Silicon Dioxide with Sol-Gel Method

2014 ◽  
Vol 609-610 ◽  
pp. 298-305
Author(s):  
Lian Min Fang ◽  
Peng Liu ◽  
Ying Chen ◽  
Zhi Wu Yu
Keyword(s):  
Coupling Agent ◽  
Silane Coupling Agent ◽  
Sol Gel ◽  
Synthesis Temperature ◽  
Surface Characteristic ◽  
Narrow Particle Size Distribution ◽  
Gel Method ◽  
Sol Gel Method ◽  
Silane Coupling ◽  
Stirring Time

The influences of temperature, compounds dosages and water on the size of nanosilica prepared by tetraethyl orthosilicate were discussed, and the transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR) were employed to investigate the characteristics of the nanosilica synthesized by the sol-gel method. Moreover, the silane coupling agent was also used to modify the surface characteristic of the nanosilica. Results showed that the influences of temperature, compounds dosages and water on the size of nanosilica had a significant impact. In fact, the optimal synthesis temperature was 45 degrees centigrade, and the stirring time was 2 hours. In this case, the nanosilica can be prepared with the grain size of 100 nm and the narrow particle size distribution. By FTIR analyzing, it can be seen that the combination of the nanosilica and the silane coupling agent was chemical reaction. In addition, the tests showed that the adsorption process finished in 40 minutes.

scholarly journals Improved Hydrophobicity of Macroalgae Biopolymer Film Incorporated with Kenaf Derived CNF Using Silane Coupling Agent

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2254
Author(s):  
Adeleke A. Oyekanmi ◽  
N. I. Saharudin ◽  
Che Mohamad Hazwan ◽  
Abdul Khalil H. P. S. ◽  
Niyi G. Olaiya ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Coupling Agent ◽  
Silane Coupling Agent ◽  
Cellulose Nanofibrils ◽  
Hydroxyl Groups ◽  
Water Contact ◽  
Silane Coupling ◽  
Cnf Films ◽  
Kenaf Bast ◽  
Thermal Stability Of

Hydrophilic behaviour of carrageenan macroalgae biopolymer, due to hydroxyl groups, has limited its applications, especially for packaging. In this study, macroalgae were reinforced with cellulose nanofibrils (CNFs) isolated from kenaf bast fibres. The macroalgae CNF film was after that treated with silane for hydrophobicity enhancement. The wettability and functional properties of unmodified macroalgae CNF films were compared with silane-modified macroalgae CNF films. Characterisation of the unmodified and modified biopolymers films was investigated. The atomic force microscope (AFM), SEM morphology, tensile properties, water contact angle, and thermal behaviour of the biofilms showed that the incorporation of Kenaf bast CNF remarkably increased the strength, moisture resistance, and thermal stability of the macroalgae biopolymer films. Moreover, the films’ modification using a silane coupling agent further enhanced the strength and thermal stability of the films apart from improved water-resistance of the biopolymer films compared to unmodified films. The morphology and AFM showed good interfacial interaction of the components of the biopolymer films. The modified biopolymer films exhibited significantly improved hydrophobic properties compared to the unmodified films due to the enhanced dispersion resulting from the silane treatment. The improved biopolymer films can potentially be utilised as packaging materials.

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