Other Nano Applications

Some examples of work at the interface between solution chemistry and nanodispersions are provided by research aimed at controlling the wettability [95] and 

PDMS = polydimethylsiloxane. (Adapted from Grumelard et al. [87], Copyright (2004), reproduced with permission of the Royal Society of Chemistry.) 

Another example of the interface between colloids and nanoscience is provided by colloidal particles onto which have been placed sticky patches that imitate hybridized atomic orbitals, including sp, sp, sp , sp d, sp d and sp d [99]. This 

Finally, microfluidics was mentioned in the earlier section. Fluid flows at the microscale can be much more strongly influenced by surface and capillary forces than is the case in macroscale systems. As a result, it is possible to passively drive fluid flows driven using only capillary or Marangoni forces. This is referred to as passive microfluidics. Conversely, active microfluidics refers to the use of active microcomponents to drive fluid flows. Active microfluidics devices use micropumps and/or microvalves to control the fluid flows and as such are an example ofMEMS. 

With so many kinds of devices being developed at such small scale, microscale and nanoscale devices are prone to failures related to their high surface area to volume ratio. Nanoscale or molecular-scale imperfections or contaminations 

---

Among other specific applications of PTs as light-emitting materials, it is necessary to mention microcavity LEDs prepared with PTs 422 and 416 [525,526] and nano-LEDs demonstrated for a device with patterned contact structure, and PT 422 blended in a PMMA matrix that emits from phase-separated nanodomains (50-200 nm) [527,528]. 

Characterization techniques continue to develop and will impact their application to zeolitic systems. Aberration corrected electron microscopes are now being used to improve our understanding of catalysts and other nano-materials and will do the same for zeolites. For example, individual Pt atoms dispersed on a catalyst support are now able to be imaged in the STEM mode [252]. The application of this technique for imaging the location of rare-earth or other high atomic number cations in a zeolite would be expected to follow. Combining this with tomography... 

All the ions studied were successfully separated and the chromatogram was obtained with the on-chip conductivity detector (Fig. 6.8). The peaks were sharp due to the small column dimensions and minimized dead volume of the integrated system and separation occurred within 90 seconds. Other important applications of nano-HPLC are summarized in Table 6.1. 

The synthesis of other nano-sized carbon structures (nanocones,9 nanopipettes10 and nanorings,11 presented in Figure le-g) has been recently reported. These structures have promising mechanical, electronic and surface properties, and are of interest for applications in nano-scale devices. 

CNTs and other nano-sized carbon structures are promising materials for bioapplications, which was predicted even previous to their discovery. These nanoparticles have been applied in bioimaging and drag delivery, as implant materials and scaffolds for tissue growth, to modulate neuronal development and for lipid bilayer membranes. Considerable research has been done in the field of biosensors. Novel optical properties of CNTs have made them potential quantum dot sensors, as well as light emitters. Electrical conductance of CNTs has been exploited for field transistor based biosensors. CNTs and other nano-sized carbon structures are considered third generation amperometric biosensors, where direct electron transfer between the enzyme active center and the transducer takes place. Nanoparticle functionalization is required to achieve their full potential in many fields, including bio-applications. 

Pramendra Kumar is an Assistant Professor in the Chemistry Department at M.J.P. Rohilkhand University, Bareilly. He obtained his Master of Science from C.C.S. University, Meerut and Master of Engineering from Delhi College of Engineering. His research interests include modification of polysaccharides, synthesis of multifunctional nano materials and synthesis of nano bio-composites for their various applications e.g. water remediation, enzyme immobilization and other adsorbent applications. 

The other common application of the QCM is as a nano-sensor proper, made sensitive to one gas or another by suitable surface treatment. Selecting the suitable coating on the electrodes of the QCM can determine selectivity and enhance sensitivity. It is not our purpose to discuss sensors in the present review. It should only be pointed out that any such sensor would have to be calibrated, since the Sauerbrey equation would not be expected to apply quantitatively. 

This chapter presents a selective glimpse of this dynamic family of spherical macromolecnles for newcomers to the topic in order to help them better appreciate the field that has been extensively reviewed elsewhere. This chapter is divided into several parts to emphasize the structmal diversity and their potential applications. First, a study of the internal structure of the dendritic architecture, emphasizing the different types, followed by a study of their interactions with other molecules or atoms, such as in the case of host-guest chemistry, molecular recognition, or encapsulation inside the dendrimer. Finally, there is a small section that will address the intermolecular interactions of dendrimers and dendrons to either themselves or other nano-objects. In this past quarter century, tens of thousands of papers have been published producing a wide variety of different dendritic architectures with varied structural components capable of novel supramolecular interactions. Therefore, only an overview describing their structure with representative examples and practical purposes will be discussed, when appropriate. 

Dendrimers and dendrons are appealing types of nanoscale, highly branched, macromolecules, which, because of their structure and properties, have attracted the interest of many researches worldwide. The preceding text has tried to summarize the different selective supramolecular aspects about their properties, structure, potential diversity, and applications to nonspecialized scientists. An introduction of these dendritic structures has combined a short description of the structure and synthesis with some historical perspectives, followed by a classification of dendritic structures, as covalent and noncovalent entities. Emphases have been given to their host-guest capacity to encapsulate small molecules, ions, or nanoparticles, as well as to interact with themselves or other nano-objects. The continued investigation in many fields of these unique architectures has produced a wide variety of branched fractal constructs, which undoubtedly will continue to spark the imagination of future synthetic architects. 

Other Industrial Applications l)Mkro/nano electronic... 

As an alternative to capillary pipettes, a micrometer controlled syringe can be used for the spotwise application of samples. One aspect of the syringe type dosage device is its selectable volume. Another aspect is the enforced delivery which facilites sample application to layers which absorb sample liquid less readily than silica gel, e.g. RP and other modified layers. The Nano-Applicator is an example of a micrometer controlled syringe. It has a dynamic volume range 50-230 nL and can be positioned with the Nanomat mentioned above. 

The flexibility of the SDF fluid transport system in nano-and micrometer thin channels enables to exploit numerous other possible applications, especially if a high degree of spatial confinement or an increase in the diffusion transport rates is required. Vankrunkelsven et al. used the SDF system for the size separation of macromolecules and micro-particles in nano- and micrometer deep channels using micro-steps [7] (Fig. 2). The separation of 0.5 and 1.0 xm carboxylated polysterene beads mixtures of Staphylococcus aureus and Saccharomyces cerevisiae, and mixtures of Saccharomyces cerevisiae and Escherichia coli cells in a micro- or nanochannel that is only slightly larger than the molecules themselves and is narrowed in a stepped structure. 

The capacity of solubilizing compounds in the droplets of a nano-emulsion gives the possibility of developing applications, implying the transport of these compounds through a continuous phase in which they are insoluble. Pharmaceutical and cosmetic applications for which nonpolar compounds are solubilized in oil droplets dispersed in aqueous media would be typical, and other possible applications in food or agrochemical fields have also been described [1,2],... 

---