Nanostructured Materials and Electronic Nose Devices: Introduction

Nanomaterials are the foundation stone of nanoscience and nanotechnology. In technical terms, nanomaterials are principally any material having at least one dimension of 100 nm or less. Nanomaterials have numerous established applications in the field of nanotechnology and display different physical–chemical characteristics from normal chemicals. In this chapter, the topic of nanostructured materials will be defined and the classification of nanostructured materials will be covered on the bases of dimensions and phase composition wise. The various physical/chemical properties that have been extraordinarily enhanced or altered through tailor-made manipulation of sizes and shapes of nanostructures are illustrated. Synthesis methods of nanostructured materials, such as chemical, physical, and additional methods, are briefly demonstrated. The differences in properties and characteristics of bulk and nanometer-sized nanomaterials, such as physical, chemical, optical, electrical, and mechanical, as well as in the structural features between those of atoms and the bulk materials, are emphasized. Deviation in most of the properties as in morphology, composition, grain size, shape, thickness, crystal structure, and even non-equilibrium phases of synthesized materials could be achieved using some sophistical methodology. With the introduction of extremely sensitive analytical apparatus such as atomic force microscopy (AFM), scanning tunneling microscopy (STM), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), it is conceivable to characterize and evaluate the produced nanostructured materials for implementations in future industrial and medical applications. Selected applications of nanostructured materials are debated. The electronic nose system is described in detail. The most common sensors applied in the e-nose systems are explained. The most useful applications of the e-nose are listed and emphasized. Outlooks and future directions of the e-nose developments and application are deliberated.