Ionic Liquid–Stabilized Titania Quantum Dots Applied in Adhesive Resin

2019 ◽  
Vol 98 (6) ◽  
pp. 682-688 ◽  
Author(s):  
I.M. Garcia ◽  
V.S. Souza ◽  
C. Hellriegel ◽  
J.D. Scholten ◽  
F.M. Collares
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Antibacterial Activity ◽  
Ionic Liquid ◽  
Sol Gel ◽  
Adhesive Resin ◽  
Transmission Electron ◽  
Polymerization Behavior

Quantum dots (QDs; 1 to 10 nm) were recently synthesized by sol-gel and used as nonagglomerated nanoparticles in adhesive resin. The sol-gel process presented a low yield and resulted in a liquid product without stability. In this study, an imidazolium ionic liquid (IL; 1- n-butyl-3-methylimidazolium tetrafluoroborate, BMI.BF4) was used as stabilizing agent to synthesize titanium dioxide QDs (TiO2QDs/BMI.BF4) via a chemical route. The product was isolated as powder after washing, centrifuging, and drying. An experimental adhesive resin was formulated by mixing methacrylate monomers and a photoinitiator system. The TiO2QDs/BMI.BF4 powder was incorporated at 2.5 (G2.5%) and 5 (G5%) wt% in the adhesive resin, and one group remained without TiO2QDs/BMI.BF4 powder as the control (Gctrl). The TiO2QDs/BMI.BF4 powder was analyzed by micro-Raman spectroscopy, thermogravimetry, and transmission electron microscopy. The dispersion of TiO2QDs/BMI.BF4 powder was analyzed in the polymerized adhesive resin with transmission electron microscopy and fluorescence microscopy. The adhesive resins were evaluated for immediate and long-term antibacterial activity, cytotoxicity, polymerization behavior, degree of conversion, softening in solvent, immediate and long-term microtensile bond strength, and fracture pattern. The TiO2QDs/BMI.BF4 powder showed peaks of anatase and rutile and 26 wt% of BMI.BF4. TiO2QDs/BMI.BF4 presented a minimum size of 1.19 nm, a maximum size of 7.11 nm, and a mean ± SD size of 3.54 ± 1.08 nm. TiO2QDs/BMI.BF4 was dispersed in the adhesive resin without agglomeration, presenting intermittent luminescence by blinking. The addition of any tested concentration of TiO2QDs/BMI.BF4 powder provided immediate and long-term antibacterial activity without cytotoxic effect against the pulp fibroblasts. Furthermore, compared with Gctrl, G2.5% showed reliable polymerization behavior and degree of conversion without differences for softening in solvent with maintenance of bond adhesion to tooth immediately and over time. Thus, the incorporation of 2.5 wt% of TiO2QDs/BMI.BF4 in adhesive resin showed reliable physical, chemical, and biological properties.

Preparation of Nano-TiO2 Modified by Ionic Liquid and its Photocatalytic Activity

2011 ◽  
Vol 322 ◽  
pp. 185-188
Author(s):  
Cheng Guang Kou ◽  
Ying Juan Hao ◽  
Rui Hong Liu ◽  
Fa Tang Li
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ionic Liquid ◽  
Chemical Structure ◽  
Degradation Rate ◽  
Diffuse Reflectance ◽  
Sol Gel ◽  
X Ray ◽  
Transmission Electron ◽  
Degradation Activity

Nano-TiO2 modified by ionic liquid was prepared by sol-gel method with Ti(OC4H9)4 as titanium source. The chemical structure of the nanopartical was characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and UV-Vis diffuse reflectance spectra (UV-Vis DRS). The results indicated that the modified TiO2 was almost entirely small nanocrystal and multihole and had high crystallinity. Radius of the modified particals had some degeree of reduction than that of the pure TiO2. The optical absorptivity of modified TiO2 is stronger than that of unmodified TiO2. The photocatalytic degradation activity of methylene blue with the prepared TiO2 was investigated. The degradation rate could reach more than 88%.

Interfacial precipitation in titania-doped diphasic mullite gels

1998 ◽  
Vol 13 (4) ◽  
pp. 974-978 ◽  
Author(s):  
Seong-Hyeon Hong ◽  
Naesung Lee ◽  
Altaf H. Carim ◽  
Gary L. Messing
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Phase Transformations ◽  
Orientation Relationship ◽  
Sol Gel ◽  
Sintered Body ◽  
Transmission Electron

Interfacial precipitation in sol-gel derived, titania-doped diphasic mullite gels was investigated using conventional and high resolution transmission electron microscopy. Rutile, anatase, and brookite precipitated on the interface between {110} planes of mullite and glass pockets in the sintered body. The formation of brookite may be attributable to the Si- and Al-rich environment during precipitation. Each polymorph of titania has a unique morphology and orientation relationship with mullite. Brookite exhibits a truncated pill box shape, and anatase displays a vermicular morphology. Quenching experiments suggest that the precipitates grow and undergo phase transformations during cooling.

Eu3+/Tb3+ Co-Doped Cerium Oxide Transparent Nanocomposite for Color-Tunable Emission

NANO ◽  
2018 ◽  
Vol 13 (10) ◽  
pp. 1850119
Author(s):  
Xiaoyan Li ◽  
Yunlong Yu ◽  
Xiangfeng Guan ◽  
Peihui Luo ◽  
Linqin Jiang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Transmission Electron Microscopy ◽  
Sol Gel ◽  
Homogeneous Precipitation ◽  
Transmission Electron ◽  
Color Tunable ◽  
Co Doped ◽  
Tunable Emission

Eu[Formula: see text]/Tb[Formula: see text] co-doped nanocomposite containing CeO2 nanocrystals was successfully prepared by an in situ sol–gel polymerization approach. High-resolution transmission electron microscopy demonstrated the homogeneous precipitation of CeO2 nanocrystals among the polymethylmethacrylate (PMMA) matrix. The thermal stability and UV-shielding capability of the obtained nanocomposite were improved with increase of CeO2 content. The tuning of the emissive color from green and yellow to red can be easily achieved by varying the dopant species and concentration. These results suggested that the obtained nanocomposite could be potentially applicable in transparent solid-state luminescent devices.

Preparation of Titanium Oxide Nanotube by Hydrothermal Process

2007 ◽  
Vol 124-126 ◽  
pp. 1165-1168 ◽  
Author(s):  
M. Qamar ◽  
Cho Rong Yoon ◽  
Hyo Jin Oh ◽  
Anna Czoska ◽  
K. Park ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Titanium Oxide ◽  
Sol Gel ◽  
Hydrothermal Process ◽  
Hollow Fibers ◽  
Systematic Analysis ◽  
Transmission Electron ◽  
Tio2 Sol ◽  
Naoh Solution

The TiO2 sol was prepared hydrothermally in an autoclave from aqueous TiOCl2 solutions as starting precursor. Hollow fibers were obtained when sol-gel derived TiO2 sol was treated chemically with NaOH solution and subsequently heated in autoclave under various conditions. A systematic analysis of the influence of different NaOH concentrations on the formation of nanotubes has been carried out using XRD and SEM. The phase structure of the synthesized material was determined by transmission electron microscopy and found that these materials are, infact, hollow fibers widely known as nanotubes. From the TEM images, the outer and inner diameters of the tubes were measured ca. 8 and about 4 nm, respectively, with several hundred nanometers in length.

Synthesis of Nanosized HMS Mesoporous Molecular Sieve in an Ionic Liquid-Water Mixture

2011 ◽  
Vol 236-238 ◽  
pp. 2110-2113
Author(s):  
Hong Liu ◽  
Meng Yang Wang ◽  
Wei Ran Cao
Keyword(s):  
Electron Microscopy ◽  
Ionic Liquid ◽  
Sol Gel ◽  
Mesoporous Molecular Sieve ◽  
Nano Particles ◽  
Water Mixture ◽  
X Ray ◽  
Transmission Electron ◽  
Adsorption Desorption ◽  
Synthesized Materials

The hexagonal mesoporous silica (HMS) nano-particles were prepared in mixture of 1-butyl-3-methyl-imidazolium tetrafluoroborate (BMIM+BF4-) ionic liquid and water by a sol-gel method. The structure and morphology of obtained materials were characterized by X-ray powder diffraction (XRD), N2adsorption-desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The influence of the amount of BMIM+BF4-was investigated. It was shown that the synthesized materials have discrete and uniform spherical morphology with the size in the range of 68-177 nm (obtained from DLS measurements), and the particle size of HMS can be controlled by varying the amount of BMIM+BF4-.

AQUEOUS SYNTHESIS OF HIGH QUANTUM YIELD AND MONODISPERSED THIOL-CAPPED CdxZn1-xTe QUANTUM DOTS BASED ON ELECTROCHEMICAL METHOD

NANO ◽  
2012 ◽  
Vol 07 (02) ◽  
pp. 1250011 ◽  
Author(s):  
JUNWEI LI ◽  
YANG JIANG ◽  
YUGANG ZHANG ◽  
DI WU ◽  
ANQI LUO ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Quantum Yield ◽  
Electrochemical Method ◽  
Large Scale ◽  
Ostwald Ripening ◽  
Visible Absorption ◽  
Aqueous Synthesis ◽  
Transmission Electron

A facile green approach has been developed to control the growth regime in the aqueous synthesis of CdxZn1-xTe semiconductor quantum dots (QDs) based on the electrochemistry method. The Low growth temperature and slow injection of Te precursor are used to prolong the diffusion controlled stage and thus suppress Ostwald ripening during the nanocrystal growth. The experimental results showed that a low concentration of Te precursor will definitely influence the growth procedure. The UV–visible absorption spectra, as well as transmission electron microscopy (TEM) shows the QDs a good monodispersity at any interval of the reaction procedure. The high-resolution transmission electron microscopy (HRTEM) images and powder X-ray diffraction (XRD) pattern suggested that the as-prepared QDs have high crystallinity and cubic structure. The size and composition-dependent fluorescent emission wavelength of the resultant CdxZn1-xTe alloyed QDs can be tuned from 460 to 610 nm, and their photoluminescent quantum yield can reach up to 70%. Especially in the wavelength range of 510–578 nm, the overall PL QYs of the as-prepared CdxZn1-xTe QDs were above 50%. The current work suggests that electrochemical method is an attractive approach to the synthesis of high-quality II-VI ternary alloyed semiconductor QDs at large-scale with a prominent cost advantage.

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