scholarly journals Monochelic Versus Telechelic Poly(Methyl Methacrylate) as a Matrix for Photoluminescent Nanocomposites with Quantum Dots

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4131
Author(s):  
Anastasija D. Jablanovic ◽  
Marianna Z. Bekanova ◽  
Ekaterina A. Litmanovich ◽  
Oleg N. Karpov ◽  
Miron A. Bugakov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Quantum Dots ◽  
Methyl Methacrylate ◽  
Ligand Exchange ◽  
Poly Methyl Methacrylate ◽  
Molecular Weights ◽  
Transmission Electron ◽  
Similarities And Differences ◽  
Optical Applications ◽  
Formation Of Complexes

Nanocomposites based on CdSe or CdSe/ZnS quantum dots (QDs) and poly(methyl methacrylate) (PMMA) of different molecular weights and functionality were synthesized by ligand exchange of oleic acid with RAFT-based PMMA. The successful ligand exchange was confirmed by dynamic light scattering in combination with the approach “macromolecules—ghosts” and transmission electron microscopy. Comparative study of mono- and telechelics of PMMA revealed the similarities and differences in their behavior in formation of complexes with QDs and the optical properties of the corresponding nanocomposites. Telechelics exhibited higher efficiency in the complex formation and seemed to be promising candidates for the construction of devices based on QDs and polymer matrix for optical applications.

scholarly journals Preparation and Photoluminescence of Transparent Poly(methyl methacrylate)-Based Nanocomposite Films with Ultra-High-Loading Pendant ZnS Quantum Dots

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1217 ◽  
Author(s):  
Jinku Xu ◽  
Dongmei Li
Keyword(s):  
Quantum Dots ◽  
Thermogravimetric Analysis ◽  
Methyl Methacrylate ◽  
Nanocomposite Films ◽  
High Loading ◽  
Pmma Film ◽  
X Ray Diffraction ◽  
Poly Methyl Methacrylate ◽  
Transmission Electron ◽  
Original Crystal

Transparent nanocomposite films containing quantum dots are popular because of their extensive applications. However, nanoparticles tend to aggregate, resulting in phase separation of the nanoparticles in the polymer matrix. Herein, we present a bulk thermo-curing copolymerization method to fabricate poly(methyl methacrylate)-based nanocomposite films with ultra-high-loading ZnS quantum dots (ZnS/PMMA), utilizing polymerizable group-capped ZnS and monomer of methyl methacrylate (MMA). We found that the nanocomposite film is highly transparent, although the transmittance decreases with the ZnS content, especially at the wavelength between 300 nm and 400 nm. The results from X-ray diffraction (XRD), transmission electron microscopy (TEM), and dynamic mechanical thermal analysis (DMTA) show that the ZnS quantum dots maintain their original crystal structure, and are uniformly dispersed in the nanocomposite films, even with a very high ZnS content (41 wt %, determined by thermogravimetric analysis). The thermogravimetric analysis shows that the nanocomposite films possess a better thermal stability than that of pure PMMA film. The photoluminescence measurements show that ZnS/PMMA nanocomposite films have good optical properties. The fluorescence intensity increases with the increment of free ZnS content to 30 wt %, and then decreases due to self-reabsorption at a higher ZnS content. The transparent ZnS/PMMA nanocomposite films have a potential application as photoluminescence material.

Graphene-Poly(Methyl Methacrylate) Composites Prepared by Two Methods

2011 ◽  
Vol 335-336 ◽  
pp. 49-53 ◽  
Author(s):  
Lin Lei ◽  
Jian Hui Qiu ◽  
Xue Li Wu ◽  
Yang Zhao ◽  
Eiichi Sakai
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Methyl Methacrylate ◽  
Graphite Oxide ◽  
Graphene Nanosheet ◽  
Poly Methyl Methacrylate ◽  
Transmission Electron ◽  
Methacrylate Monomer ◽  
Methyl Methacrylate Monomer ◽  
Scanning Electron

Graphene-poly(methyl methacrylate) (GNS-PMMA) composites were prepared by two methods. Graphite oxide nanosheet-poly(methyl methacrylate) (GO-PMMA) composites were prepared of methyl methacrylate monomer and the presence of graphite oxide (GO). Then the GO-PMMA composites were reduced to graphene nanosheet-poly(methyl methacrylate) by using hydrazine hydrate. The obtained composites were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The composite exhibited conductivities in the 1.58×10-9-4.21 S/cm range, depending on the amounts of graphite oxide and PMMA.

Insight into the structure of polystyrene-poly(methyl methacrylate) core-shell particles synthesized by seeded suspension polymerization

2020 ◽  
pp. 096739112098276
Author(s):  
H Rostami ◽  
F Abbasi ◽  
K Jalili ◽  
E Mehravar ◽  
M Najafpour
Keyword(s):  
Electron Microscopy ◽  
Methyl Methacrylate ◽  
Suspension Polymerization ◽  
Particle Morphology ◽  
Polymer Particle ◽  
Outer Shell ◽  
Core Shell ◽  
Poly Methyl Methacrylate ◽  
Transmission Electron ◽  
Shell Particles

Core-shell particles were synthesized employing seeded suspension polymerization. Suspension polystyrene (PS) particles were used as seeds, and poly(methyl methacrylate) (PMMA) was synthesized in the presence of polystyrene seeds. A combination of solvent extraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy techniques were employed to study the structure and morphology of synthesized particles. The results suggested a core-inner shell-outer shell structure for the synthesized particles in which the PS core was covered by a PMMA-rich inner shell and a very thin PS-rich outer shell. The size and concentration of PMMA domains decreased from the outer shell toward the core of the particle, and particle morphology was mainly controlled by the limitations to the diffusion of MMA through the polymer particle.

Microspherical Poly(methyl methacrylate)/Multiwalled Carbon Nanotube Composites Prepared via In Situ Dispersion Polymerization

2007 ◽  
Vol 7 (11) ◽  
pp. 4045-4048 ◽  
Author(s):  
Hun-Sik Kim ◽  
Seung Jun Myung ◽  
Rira Jung ◽  
Hyoung-Joon Jin
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotube ◽  
Methyl Methacrylate ◽  
Dispersion Polymerization ◽  
Multiwalled Carbon ◽  
Poly Methyl Methacrylate ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotube ◽  
Nanotube Composites

In this study, microspherical poly(methyl methacrylate)/multi-walled carbon nanotube (PMMA/MWCNT) composites were directly prepared by in situ dispersion polymerization using poly (N-vinylpyrrolidone) in methanol media. PMMA/MWCNT microspheres having a diameter of 2.6∼3.9 μm and a molecular weight of 58,000∼65,000 g/mol with a 15.7∼19.5% coefficient of variation (Cv) were synthesized. The morphology of the synthesized composite was investigated using scanning electron microscopy and transmission electron microscopy. The experimental results demonstrated that MWCNTs are well dispersed and embedded in the final PMMA/MWCNT microspheres. The prepared PMMA/MWCNT microspheres were investigated in terms of their capacity to serve as an electrorheological (ER) materials.

Observation of solid-state reaction between a thin yttria film and a (0001) α-alumina substrate

1994 ◽  
Vol 52 ◽  
pp. 644-645
Author(s):  
J. R. Heffelfinger ◽  
C. B. Carter
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Solid State Reaction ◽  
Yttrium Aluminum Garnet ◽  
Secondary Phase ◽  
Ceramic Composites ◽  
Alumina Substrate ◽  
Transmission Electron ◽  
Alumina Fibers ◽  
Optical Applications

Transmission-electron microscopy (TEM), scanning-electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS) were used to investigate the solid-state reaction between a thin yttria film and a (0001) α-alumina substrate. Systems containing Y2O3 (yttria) and Al2O3 (alumina) are seen in many technologically relevant applications. For example, yttria is being explored as a coating material for alumina fibers for metal-ceramic composites. The coating serves as a diffusion barrier and protects the alumina fiber from reacting with the metal matrix. With sufficient time and temperature, yttria in contact with alumina will react to form one or a combination of phases shown by the phase diagram in Figure l. Of the reaction phases, yttrium aluminum garnet (YAG) is used as a material for lasers and other optical applications. In a different application, YAG is formed as a secondary phase in the sintering of AIN. Yttria is added to AIN as a sintering aid and acts as an oxygen getter by reacting with the alumina in AIN to form YAG.

L-cysteine functionalized graphene quantum dots for sub-ppb detection of As (III)

2021 ◽  
Author(s):  
Md. Farhan Naseh ◽  
Neelam Singh ◽  
Jamilur R. Ansari ◽  
Ashavani Kumar ◽  
Tapan Sarkar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Quantum Dots ◽  
Room Temperature ◽  
Graphene Quantum Dots ◽  
Optical Characterization ◽  
Functionalized Graphene ◽  
Transmission Electron ◽  
Sensitivity And Selectivity ◽  
Structural Characterizations

Abstract Here, we report functionalized graphene quantum dots (GQDs) for the optical detection of arsenic at room temperature. GQDs with the fluorescence of three fundamental colors (red, green, and blue) were synthesized and functionally capped with L-cysteine (L-cys) to impart selectively towards As (III) by exploiting the affinity of L-cys towards arsenite. The optical characterization of GQDs was carried out using UV-Vis absorption spectroscopy, Fourier transform infrared spectroscopy, and fluorescence spectrometry and the structural characterizations were performed using transmission electron microscopy. The fluorescence results showed instantaneous quenching in intensity when the GQDs came in contact with As (III) for all test concentrations over a range from 0.025 ppb to 25 ppb, which covers the permissible limit of arsenic in drinking water. The experimental results suggested excellent sensitivity and selectivity towards As (III).

Bovine Serum Albumin Conjugation in Superparamagnetic/Poly(methyl methacrylate) Nanoparticles as an Alternative for Magnetic Enzyme-Linked Immunosorbent Assays

2021 ◽  
Vol 21 (11) ◽  
pp. 5493-5498
Author(s):  
Paulo Emilio Feuser ◽  
Camila Guindani ◽  
Jonathann Correa Possato ◽  
Jaqueline Pereira Guessi ◽  
Arthur Poester Cordeiro ◽  
...  
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Methyl Methacrylate ◽  
Bovine Serum ◽  
Protein Quantification ◽  
Elisa Assay ◽  
Poly Methyl Methacrylate ◽  
Transmission Electron ◽  
Superparamagnetic Properties ◽  
Significant Attention

Nanomaterials, such as magnetic nanoparticles have attracted significant attention of medical area due to their capacity to improve the performance of immunoassays. Therefore the aim of this work was to study the bovine serum albumin (BSA) conjugation in superparamagnetic (MNPs)/poly(methyl methacrylate) (PMMA) nanoparticles with further characterization and application in enzyme-linked immunosorbent (ELISA) assay. The successful conjugation of BSA in MNPs- PMMA nanoparticles was confirmed by several techniques, including light scattering, zeta potential, transmission electron microscopy (TEM) and Lowry protein quantification assay. The superparamagnetic properties were confirmed by vibrating sample magnetometer. BSA conjugated MNPs-PMMA nanoparticles presented higher interactions with antibody than free BSA. The BSA + MNPs-PMMA nanoparticles (magnetic ELISA assay) reduced the time and increased the sensibility of traditional ELISA assay, reinforcing the idea that the use these nanomaterials are an excellent alternative for the immunoassays field.

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