Nano needles

In 1994, we proposed that a metallic needle having a nano-tip at its apex be employed as a nano-light-source for microscopy attaining nanometric spatial resolution [2]. Later, we expanded the technique to Raman spectroscopy for molecular nano-identification, nano-analysis and nano-imaging. In this chapter, we give a brief introduction to local plasmons and microscopy using a metallic nano-needle to produce the local plasmons. Then, we describe the microscope that we built and... 

Yin, A., and Xu, A. (2006), Fabrication of highly-ordered and densely-packed sihcon nano-needle arrays for bio-sensing applications, Mater. Res. Soc. Symp. Proc., 900E. 

Copper hydroxide nano-needle arrays also have been electrosynthesized and applied for fabrication of SHSs [24]. The nano-needle arrays were synthesized by... 

Figure 2. SEM images of copper hydroxide nano-needle arrays before (a) and after (b) treatment with an ethanol solution of n-dodecanethiol for 1.5 h (the nano-needles were deposited at a eonstant eurrent density of 1.5 vaAJar in 2.0 mol/1 KOH solution for 3 C/cm ). Inset of (b) image of a water droplet on the film. Reproduced with permission from [24]. Copyright 2006 American Chemical Society.

When a nano assembly is involved with a directional interaction, the most likely nano element will be a film or surface-based nanoscale operation. Examples include most of the nano-structured films regardless of their detailed morphology. Nano porous film, nano layered film, and nano patterned film are among them. It also includes most of the nanoscale products that are obtained as a result of directional growth (from the spherical-shape) such as nano rods, nano needles, and nanotubes. A good deal of... 

Another largely unexplored area is the change of dynamics due to the influence of the surface. The dynamic behavior of a latex suspension as a model system for Brownian particles is determined by photon correlation spectroscopy in evanescent wave geometry [130] and reported to differ strongly from the bulk. Little information is available on surface motion and relaxation phenomena of polymers [10, 131]. The softening at the surface of polymer thin films is measured by a mechanical nano-indentation technique [132], where the applied force and the path during the penetration of a thin needle into the surface is carefully determined. Thus the structure, conformation and dynamics of polymer molecules at the free surface is still very much unexplored and only few specific examples have been reported in the literature. 

Micro- (and even nano-) electrode arrays are commonly produced with photolithography and electronic beam techniques by insulating of macro-electrode surface with subsequent drilling micro-holes in an insulating layer [136, 137], Physical methods are, however, expensive and, besides that, unsuitable for sensor development in certain cases (for instance, for modification of the lateral surface of needle electrodes). That s why an increasing interest is being applied to chemical approaches of material nanostructuring on solid supports [140, 141],... 

In Tables 9.9-3 to 9.9-5 a summary of the recrystallization process of pharmaceuticals and bio-polymers, and co-precipitation by supercritical anti-solvent is presented. In Figures 9.9-1 and 9.9-2 examples of very long needle crystal and nano-particles are reported. 

Several modifications of the ESI technique have been introduced, principally micro-electrospray14 and nano-electrospray15 that have the advantage of using much lower flow rates, reducing the amount of analyte needed for a mass-spectrometric analysis this is performed using adapted probed tips. When performing nanospray, the sample is loaded into a fine hollow needle with a... 

Electro-conductive rubber material Because of its great strength and much lower price than such expensive metals as silver and palladium, nano copper or copper-silver double metal powder can be used in the electronics industry to take the place of those expensive metals for the preparation of electro-conductive rubbers [191], electro-conductive slurry, and electrode materials etc. in addition, the copper-silver double metal powder has the characteristic of antibiosis. For such use nano copper or copper-silver powder should be needle-like crystalline the nano copper powders of sphere-like crystalline has very low electro-conductivity. 

Figure 14.4 Nano copper of needle-like form obtained in the feeding mode III. 14.4.2.2 Influence of CuCI2 concentration...

Balzer, F. and Rubahn, H.-G. (2002) Laser-controlled growth of needle-shaped organic nanoaggregates. Nano Letters, 2, 747-50. 

The nano-electrospray (nanoES) source is essentially a miniaturized version of the ES source. This technique allows very small amounts of sample to be ionized efficiently at nanoliters per minute flow rates and it involves loading sample volumes of 1-2 pi into a gold-coated capillary needle, which is introduced to the ion source. Alternatively for on-line nanoLC-MS experiments the end of the nanoLC column serves as the nanospray needle. The nanoES source disperses the liquid analyte entirely by electrostatic means [27] and does not require assistance such as solvent pumps or nebulizing gas. This improves sample desolvation and ionization and sample loading can be made to last 30 minutes or more. Also, the creation of nanodroplets means a high surface area to volume ratio allowing the efficient use of the sample without losses. Additionally, the introduction of the Z-spray ion source on some instruments has enabled an increase in sensitivity. In a Z-spray ion source, the analyte ions follow a Z-shaped trajectory between the inlet tube to the final skimmer which differs from the linear trajectory of a conventional inlet. This allows ions to be diverted from neutral molecules such as solvents and buffers, resulting in enhanced sensitivity. 

Reduction of sample consumption during protein characterization by ESl-MS is the main objective in designing ESI needles for flow-rates lower than 1 pEmin. Such needles can also be applied in the on-line MS coupling of low flow-rate techniques like CE and nano-LC (Ch. 17.2 and Ch. 17.5.2). 

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