Nanoneedles

Figure C2.17.2. Transmission electron micrograph of a gold nanoneedle. Inverse micelle environments allow for a great deal of control not only over particle size, but also particle shape. In this example, gold nanocrystals were prepared using a photolytic method in surfactant-rich solutions the surfactant interacts strongly with areas of low curvature, thus continued growth can occur only at the sharjD tips of nanocrystals, leading to the fonnation of high-aspect-ratio nanostmctures [52].

Cizeron J, Robertson S T and Colvin V L 1999 Preparation of gold nanoneedles, in preparation... 

The alternation of temperature in a hydrothermal reaction was demonstrated to be crucial in changing the crystal phases or morphologies of nanomaterials. In the case of K2Cr207, when the reaction temperature was increased to 180 °C, K-OMS-2 microspheres consisting of nanoneedles were synthesized in contrast to the nanoduster arrays composed of tetragonal prism nanorods synthesized at 120 °C (Figure 8.1a-c). In the case of Na2Cr207, when the reaction temperature was 100 °C, Na-OMS-2 phase was formed. However, when the reaction temperature was... 

CNTs Behave with Their Needle-Like Shape Nanoneedles... 

Chen et al. (2007) have developed a nanoinjector that injects compounds immobilized on MWNT-atomic force microscopy (AFM) tips into the cells. First, a MWNT-AFM tip was fabricated from a normal AFM tip with an MWNT on one end. Next, a compound of interest was immobilized on the MWNT-AFM tip through a disulfide bond linkage. After MWNT-AFM tip was tapped on the cell, the cantilever was further lowered and the MWNT nanoneedle then penetrated the membrane. Once inside the cell, the disulfide linkage was broken under the cells reducing environment and the compound of interest was released inside the cell. The MWNT-AFM tip was then removed from the cell. In this study, protein was... 

O., Netzer, F.P., Teichert, C., Resel, R. and Ramsey, M.G. (2004) Oriented sexiphenyl single crystal nanoneedles on Ti02 (110). Advanced Materials (Deerfield Beach, Fla.), 16, 2159... 

Silicon based Silicon, silicon dioxide Porous nanoparticles, nanoneedles... 

Figure 7. Micro-photoluminescence spectra of the nanoneedle of Fig. 5 for D 790 nm at two different polarizer azimuth orientations shifted vertically for clarity. The modulation of the VIS band almost disappears when detecting the TE mode. Thus, the resonances are mainly TM polarized. The inset shows the ratio P = (Tm Te) (Tm + e), that visualizes the TM-WGMs as distinguishable peaks. The polarization effect has been found to be independent of the polarization of excitation.

We have prepared nanoneedles of mixed Co oxide using the sonochemical method for decomposing metal complexes. Resulted nanoparticles are rather well-ordered structures with the average size of 23 nm in length and 5 nm in diameter. Magnetic measurements revealed the ferromagnetic transition at 25 K, which can be explained by the chemical surface modification of the particles. 

Typical TEM micrographs are shown in Figs. 2a and 2b. Sample 1 contains nanoneedles of about 19 nm in length and 5 nm in diameter which are congregated with each other into more complex web-like structures. Sample 2 also contains nanoneedles (28 nm in length, 4 nm in diameter), however, along with spherical nanoparticles (7 nm in diameter). 

FIGURE 25-38 Detection of dopamme at a multiwall carbon nanolube-based nanoneedle electrode. Differential-pulse voltamrnograms of dopamine at the nanoneedle electrode in various concentrations irom 100 to 1000 pM, Inset is the calibration curve. (From H. Boo et al Anal. Chem., 2006. 78, 617 With permission. Copyright 2006 American Chemical Society ... 

The ionic liquid l- -butyl-3-methylimidazolium tetrafluorob-orate has been used to synthesize nanoneedles and nanorods of manganese dioxide (MnO,)." Crystalline silica nanowires were prepared by Deepak et al."" by a carbothermal procedure. Crystalline SiO, nanowires have also been prepared by a low-temperature iron assisted hydrothermal procedure. ... 

During sintering of compacted ZnO-SnO2 and ZnO-MgO powders at high temperature under argon flow, stacks of oriented nanoplates grow on the sample surface. The nanoplates consist of ZnO with few % of Sn or Mg. The formation of the stacks in Sn doped samples is explained by the appearance of internal stresses and slip. CL and EDS show that Sn or Mg are distributed over the nanoplates and the nanoneedles associated to some nanoplate stacks. 

Nanoneedle YF3 The microwave and IL methods developed by our group have been found to be very efficient and simple, compared to other methods employed in the past for the fabrication of rare earth fluorides. To obtain yttrium fluoride nanoneedles we first had to prepare yttrium nitrate, which is obtained by refluxing yttrium oxide in a nitric acid. In the next step, the yttrium nitrate is dissolved in the IL, and then heated in a domestic microwave oven. We examined the product during the course of... 

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