A Highly Transparent and Luminescent Hybrid Based on the Copolymerization of Surfactant‐Encapsulated Polyoxometalate and Methyl Methacrylate

Abstract

ExperimentalSample Preparation: A thin layer of photoresist (Shipley S1818, Shipley, MA) was spin-coated on cleaned glass substrates. A monolayer of sacrificial nanospheres was generated by drop-casting a 0.1 % solution of polystyrene colloids (150 nm; Duke Scientific, CA), which was allowed to dry overnight in a clean-zone hood to minimize contamination of the samples by dust and to stabilize the rate of evaporation. After the arrays of beads dried, metal films in various thicknesses were deposited by conventional electron-beam evaporation. The sample substrate was placed above the metal-pellet sources with a certain tilt angle (∼ 60°) with respect to the substrate surface. The substrate was rotated at a constant speed (∼ 60 revolutions per minute, rpm) during the deposition. The metal-coated colloids were released from the glass support into an aqueous suspension by lift-off with acetone. Next, the coated polymer nanospheres were collected by centrifugation (∼ 5000 rpm, 5-10 min) and suspended in toluene to dissolve the polystyrene. The sample was then centrifuged and washed three to four times in water. The nanocrescents were collected and resuspended in water or ethanol to form diluted colloids.Fluorescence Imaging and Raman Microspectroscopy: A microscopy system combining fluorescence imaging and Raman spectroscopy was used to monitor the fluorescence intensity and to acquire Ramanscattering spectra from single nanocrescents. The system consisted of a Carl Zeiss Axiovert 200 inverted microscope (Carl Zeiss, Germany) equipped with a high-speed, high-sensitivity digital camera (Cascade 512B, Roper Scientific, NJ), and a 300 mm focal length monochromator (Acton Research, MA) with a 1024 pixel × 256 pixel cooled spectrograph charge-coupled device (CCD) camera (Roper Scientific, NJ). The time-resolved fluorescence images of the nanocrescents were taken using the Cascade camera at a frame rate of 10 frames per second, a 40× objective lens (numerical aperture NA= 0.8), a fluorescein isothiocyanate (FITC) fluorescence filter set, and a 100 W mercury lamp for illumination. A 785 nm semiconductor laser was used in our experiments as the excitation source of Raman scattering, and the laser beam was focused by a 100× objective lens on the nanocrescent. The excitation power was measured by a photometer (Newport, CA) to be ∼ 1 mW. The Raman scattering light was then collected through the same optical pathway through a long-pass filter and analyzed by the spectrometer.

Lanthanide‐Containing Light‐Emitting Organic–Inorganic Hybrids: A Bet on the Future

“…LMCT states (O ! W) are also present in the excitation spectra of surfactant-encapsulated POM clusters [100,101] and W-MoK 13 [Eu(SiMo x W 11-x O 39 ) 2 ] (x ¼ 1, 3, 5) heteroPOMs incorporated into a silica-gel (O ! W and O !…”

“…All this research activity has been focused on amorphous organic-inorganic hybrids, either incorporating ionic salts [55][56][57][58][59][60][61][62][63][64][65][66][67] and organic complexes [23,30,[68][69][70][71][72][73][74][75][76][77][78][79][80][81][82] or formed through the covalent attachment bonding grafting of those complexes to the siliceous domains, [83][84][85][86][87][88][89][90][91][92][93][94][95][96][97] (Scheme 1, route A). Functionalized nano-building blocks (NBBs), such as metal-oxo clusters, [98,99] polyoxometalates (POMs), [100,101] and nanopartic...…”

Design of Hydrophobic Polyoxometalate Hybrid Assemblies Beyond Surfactant Encapsulation

“…Recently, cationic surfactants have been applied to assembly with POM clusters [11] and the resulting surfactant-encap-A C H T U N G T R E N N U N G sulated clusters (SECs) are compatible with organic functional groups, which have been successfully assembled into polymeric [12] and liquid crystalline matA C H T U N G T R E N N U N G erials. [13] These materials show it is possible to retain the basic physical and chemical properties of the POM clusters, however, it should be emphasized that mainly electrostatic interactions exist Abstract: Grafting of C-6, C-16 and C-18 alkyl chains onto the hydrophilic Mn-Anderson clusters (compounds 2-4) has been achieved.…”

A Novel, Luminescent, Silica‐Sol–Gel Hybrid Based on Surfactant‐ Encapsulated Polyoxometalates

“…[6] We have also employed polymerizable surfactants as a bridge to fabricate POMsbased bulk polymer materials successfully. [7] In light of this result, we have designed and synthesized a functional cationic surfactant with two hydroxyl terminal groups: di(11-hydroxyundecyl)dimethylammonium bromide (DOHDA, Supporting Information). We attempted to combine the encapsulation method and the sol-gel technique by using DOHDA as a bridging unit to obtain a stable, POM-based, silica-sol-gel hybrid material.…”