Ligand displacement induced morphologies in block copolymer/quantum dot hybrids and formation of core–shell hybrid nanoobjects

This article reports on the ligand displacement induced morphologies in block copolymer/quantum dot hybrids and further formation of core–shell nano-objects from them.

Hybrid Multilayered Plasmonic Nanostars for Coherent Random Lasing

Here, we report that hybrid multilayered plasmonic nanostars can be universally used as feedback agents for coherent random lasing in polar or nonpolar solutions containing gain material. We show that silver-enhancement of gold nanostars reduces the pumping threshold for coherent random lasing substantially for both a typical dye (R6G) and a typical fluorescent polymer (MEH-PPV). Further, we reveal that the lasing intensity and pumping threshold of random lasers based on silver-enhanced gold nanostars are not influenced by the silica coating, in contrast to gold nanostar-based random lasers, where silica-coated gold nanostars support only amplified spontaneous emission but no coherent random lasing.

Encapsulation of MEH-PPV:PCBM Hybrids in the Cores of Block Copolymer Micellar Assemblies: Photoinduced Electron Transfer in a Nanoscale Donor-Acceptor System

The objective of this work is to demonstrate that conjugated polymer:fullerene hybrid nanoparticles encapsulated in the hydrophobic cores of triblock copolymer micelles may successfully act as spatially confined donor-acceptor systems capable of facilitating photoinduced charge carrier separation. To this end, aqueous dispersions of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) nanoparticles were first prepared by solubilization of the polymer in the cores of poly(oxyethylene)-poly(oxypropylene)-poly(oxyethylene) triblock copolymer, Pluronic F-127 micelles. A number of significant optical spectroscopic changes were observed on transfer of the conjugated polymer from a nonaqueous solvent to the aqueous micellar environment. These were primarily attributed to increased interchain interactions due to conjugated polymer chain collapse during encapsulation in the micellar cores. When prepared in buffer solution, the micelles exhibited good long-term collodial stability. When MEH-PPV micelles were blended by the addition of controlled amounts of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), the observed correspondence of photoluminescence emission quenching, quantum yield decreases, and emission lifetime shortening with increasing PCBM concentration indicated efficient photoinduced donor-to-acceptor charge transfer between MEH-PPV and the fullerenes in the cores of the micelles, an assignment that was confirmed by transient absorption spectroscopic monitoring of carrier photogeneration and recombination.

The fluorescent interactions between amphiphilic chitosan derivatives and water-soluble quantum dots

The LCC-CdTe quantum dots (QDs) hybrid was fabricated by mixing the N-lauryl-N, O-carboxymethyl chitosan (LCC) micelle with water-soluble CdTe QDs in an aqueous solution via hydrophobic forces and the electronic attraction. The structures of LCC and LCC-CdTe QDs hybrid were determined by differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR) spectroscopy and transmission electron microscopy (TEM). The results showed that the lauryl and carboxymethyl were successfully grafted to chitosan oligosaccharide (CSO), and a number of CdTe QDs were encapsulated by LCC micelle to form a core/shell structure. The tested results of the fluorescent characteristics of LCC, CdTe QDs and LCC-CdTe QDs hybrid showed that there were some obvious fluorescent interactions between LCC and CdTe QDs. Meanwhile, with the change in LCC space structure, the fluorescent interactions between LCC and QDs showed different fluorescent characteristics. The QDs fluorescent (FL) intensity increased first and then decreased to almost quenching, while LCC FL intensity decreased continually.

Long-term stability of CdSe/CdZnS quantum dot encapsulated in a multi-lamellar microcapsule

We developed a novel and easy encapsulation method for quantum dots (QDs) using a partially oxidized semi-crystalline polymeric material which forms a micron-sized granule with a multi-lamellar structure from a dilute solution. The QDs were highly dispersed in the granule in such a way that they were adsorbed on the lamella with ∼12 nm spacing followed by lamellar stacking. The QDs were heavily loaded into the granule to 16.7 wt% without aggregation, a process which took only a few minutes. We found that the quantum yield of the QDs was not degraded after the encapsulation. The encapsulated QD-silicone composite exhibited excellent long-term photo- and thermal stability with its initial photoluminescence intensity maintained after blue LED light radiation for 67 days and storage at 85 °C and 85% relative humidity for 119 days.

Multifunctional core–shell polymer–inorganic hybrid nanofibers prepared via block copolymer self-assembly

A simple approach for fabricating multifunctional core–shell nanofibers via self-assembly of block copolymer has been demonstrated. The approach is versatile and could easily be extended to a range of targeted combination of nanoparticles.

A novel carboxymethyl chitosan-quantum dot-based intracellular probe for Zn2+ ion sensing in prostate cancer cells

In this paper, we fabricated novel carboxymethyl chitosan-coated CdTe quantum dots (CMC-CdTe QDs) via the electrostatic interaction between amino groups in the carboxymethyl chitosan polymeric chains and carboxyl groups of the CdTe QDs. Carboxymethyl chitosan on the surface of CdTe QDs had strong binding ability with Zn(2+), resulting in the obvious enhancement of the photoluminescence of CdTe QDs. The photoluminescence intensity of CMC-CdTe QDs probe was proportional to the concentration of Zn(2+) in the range of 5.0 × 10(-6) to 5.0 × 10(-3) mol l(-1). The detection limit for Zn(2+) was 4.5 × 10(-6) mol l(-1). The experimental results indicate that the CMC-CdTe QDs possess favorable cell compatibility, good sensitivity and selectivity for intracellular Zn(2+) sensing, and are promising candidates for cellular imaging and sensing in prostate cancer cells. The present study also provides an approach for the further development of nanoprobes dedicated to intracellular sensing.

Cross-linked reverse micelles with embedded water pools: a novel catalytic system based on amphiphilic block copolymers

The shell cross-linked reverse micelles were used as a more reactive and recoverable catalytic system.

Multifunctional nanoparticle-loaded spherical and wormlike micelles formed by interfacial instabilities

Hybrid spherical and wormlike amphiphilic block copolymer micelles are formed through evaporation-induced interfacial instabilities of emulsion droplets, allowing the incorporation of pre-synthesized hydrophobic inorganic nanoparticles within the micelle cores, as well as co-encapsulation of different nanoparticles. This encapsulation behavior is largely insensitive to particle surface chemistry, shape, and size, thus providing a versatile route to fabricate multifunctional micelles.