Photoluminescent Polymer/Quantum Dot Composite Nanoparticles

Abstract

Core−shell CdS/SiO2 nanoparticles were prepared and modified with the atom transfer radical polymerization (ATRP) initiator 3-(2-bromopropionyloxy)propyl dimethylethoxysilane (BIDS). The initiator-modified nanoparticles were then used as macroinitiators for the polymerization of methyl methacrylate (MMA) catalyzed by NiBr2(PPh3)2. These hybrid polymer/inorganic nanoparticles could be cast into films that retained the photoluminescence of the precursor CdS nanoparticles and showed even dispersal of the CdS/SiO2 cores throughout the PMMA matrix. These hybrid nanoparticles are versatile structures: their films can be processed from solution and show uniform dispersion of the inorganic phase throughout the host organic matrix on the microscopic level. These nanoparticles also have components whose structures and compositions can be altered to introduce new properties to the material (i.e., the luminescence of the inorganic core or the conductivity of the polymer arms) and to allow for self-assembly of the material (via the structure and composition of the polymer arms).

Engineering of poly(ethylene glycol) chain-tethered surfaces to obtain high-performance bionanoparticles

“…Since the use of ligand-conjugated QDs as fluorescent biolabeling reagents was reported in 1998 by the groups of Alivisatos [51] and Nie [52], many approaches to QD applications have been realized in the bioanalytical field such as DNA sequencing, tissue immune-diagnostics and single molecular imaging [53][54][55][56][57][58][59][60][61][62][63][64][65][66]. The advantages of QDs as biolabeling agents are (i) tunability of the emission wavelength by changing the particle size, (ii) a sharp and symmetrical emission peak, (iii) the high intensity and long lifetime of the fluorescence and (iv) a wide range of excitation wavelengths.…”

“…Several approaches to fluorescence activation based on the confinement of charge carriers within the QD cores have been reported [59][60][61][62]. For example, the coordination of electron-donating compounds such as amines and phosphine oxide significantly increases the fluorescence intensity [63,64].…”

Novel Miscible Blends Composed of Poly(Methyl Methacrylate) and 2,2-Bis(3,4-Carboxyphenyl)Hexafluoropropane Dianhydride-Based Polyimides with Optical Grade Clarity

“…1) PMMA has excellent clarity with high rigidity and toughness as a homopolymer, though deficient characteristics of PMMA such as low impact strength, poor radiation, thermal stability, and solvent resistance deter its application in some areas. [1][2][3][4][5] There has been great interest in polymer blends for quite some time, as polymer blending is a fast and economical way of improving the properties of commercially available polymers without the laborious development of new polymers. [6][7][8][9][10] However, the physical properties of the newly developed polymer blends are strongly dependent upon the phase miscibility.…”

“…23,24) This work examines blends of PMMA with 6FDA-based polyimides to develop miscible blends that overcome the drawbacks of PMMA and have optical-grade clarity. [4][5][6][7] The miscibility of polymer blends is often judged from specimens prepared by melt blending or solution casting methods. However, an inappropriate choice in temperature or solvent may lead to an erroneous judgment about miscibility due to phase separation resulting from LCST type phase behavior,…”

Preparation and a Time-Resolved Fluoroimmunoassay Application of New Europium Fluorescent Nanoparticles

“…After the solution was stirred for 24 h at room temperature, the nanoparticles were isolated from the microemulsion by adding acetone, centrifuging, and washing with ethanol and water several times to remove any surfactant and unreacted materials. Different from luminophore-doped silica nanoparticles, such as Ag/SiO2, 8 Au/SiO2, 9 CdS/SiO2, 10 and 2,2′-bipyridine-Ru 2+ chelate/SiO2 4 nanoparticles, since the Eu 3+ chelate molecules were covalently bound to silicon atoms in the nanoparticles to protect the nanoparticles from dye leaking, the fluorescence of the new nanoparticles is highly stable during the washing, surface modification, bio-labeling, and bioassay processes. Furthermore, because the nanoparticles were prepared by the copolymerization of APS-BHHCT-Eu 3+ , free APS and TEOS, free amino groups, have been directly introduced to the nanoparticle's surface.…”