Chemical Modification of Solid Surfaces by the Use of Additives

Anisotropic nanostructures (ANs) have increasingly become attractive materials in the current decade due to the direction-dependent properties associated with them. The materialization of ANs is highly delicate, where sharp edges and vertices synthesis is very crucial. There are a few factors that play an important role in the synthesis of ANs, such as surfactants, pH, temperature, etchants, choice of reducing agent, metal precursor, reaction time, solvent, etc. This chapter discusses how surfactants affect the growth of ANs. Although several surfactants are used for the synthesis of ANs, we have focused on the surfactants, such as cetyltrimethylammonium bromide (CTAB) polyvinylpyrrolidone (PVP), cetyltrimethylammonium chloride (CTAC), and binary surfactant mixture used for the synthesis of Au, Ag, and Cu nanostructures. An overview of various types of surfactants and the importance of the choice of surfactant, which is necessary for the synthesis of the particular nanostructure, is presented. Also, the change in nanostructure formation with the change in percentage assay of surfactant is discussed. The contemporary strategies and advantages of binary surfactant mixture over the mono-surfactant are comprehensively reviewed. The challenges in the synthesis of particular nanostructures with the required size and morphology are highlighted.

Quantum dots (QDs) are nanoparticles with unique physical and chemical properties. QDs seem to show the greatest promise as biosensing, in vivo imaging techniques, nanomedicine, drug delivery, molecular pathology, and photovoltaics. Thus, the study of the QDs is one of the newest rapidly growing eras in modern chemistry. Such materials might have potential risks to human health, but still, the use of these materials is growing quickly. Specifically, the matter of QDs’ toxicity is very important, which is one of the major barriers in the growing world. This chapter describes the protocols related to the preparation of QDs, characterization techniques, their properties and applications and special consideration on the toxicology as well as surface modification of CdTeQDs.

Slurry is a novel concept that facilitates navigation of hard material from the place of origin to the transformation yard through a pipeline in the vehicles of various liquids. The viscosity of slurry arises largely due to the conglomeration of coal particle due to the vander Waal force arising among the particles. To maintain a good stability for dispersion of CWS, the viscosity of the concentrated slurry should be high; however, during its transportation in the pipeline, slurry viscosity should be low so that it can flow easily. This chapter describes the preparation and stabilization of high concentrated coal water slurry by using surfactant and a mixture of surfactant. The flow behavior of the slurry is discussed by variation of shear rate, coal concentration, additive or surfactant concentration, temperature and pH of the slurry. Bingham plastic model is used to explain the rheological characteristics of slurry, which indicates a non-Newtonian flow. The mechanism of stabilization of the slurry is discussed on the basis of the structural characteristics of the surfactant.

In this century, the biggest environmental concern is the pollution caused due to the contamination of various industrial discharges. The majority of the liquid discharges contain hazardous and various toxic non-degradable components, which are carcinogenic and cause health hazards. The industrial effluent containing waste dyes, pesticides and pharmaceuticals wastes are the major concern as these wastes bear a substantial quantity of hazardous organic components. Therefore, the relevant processing technologies are warranted to mitigate such issues. In the past four decades, there has been an abundant investigation for adsorptive removal of these waste dyes and other organic pollutants using numerous sorbents, including charcoal, activated carbon, clay materials, organic extracts of the plants, nano-materials and many others. However, with the development of various activated carbon in due course of time with the perspective of process economy and effective adsorption behavior for removing these organic pollutants, there has been a tremendous focus and growing interest for their utilization in this domain. The sources of waste pollutants, development of activated adsorbents, fundamental characteristics properties of the adsorbent, sorption studies on removal of these adsorbent, sorption mechanism including sorption kinetics, isotherm and thermodynamics on the interaction of activated adsorbent with organic pollutant and future perspective are comprehensively discussed and reported.

For high concentration disposal of fly ash slurry, a detailed investigation of rheological behavior is required. The addition of a surfactant to slurry reduces surface tension, thereby increasing its spreading and wetting properties of solid particles. Thus the requirement of the amount of water, as well as energy during pipeline transportation, is reduced. The present chapter describes in detail the generation of fly ash from a thermal power plant and its stabilization for pipeline transportation. The rheological behavior of fly ash samples is studied in the presence of some natural and synthetic surfactants. A suitable rheological model is used to discuss the relationship between various rheological parameters. The addition of a surfactant may reduce the viscosity of the slurry. Moreover, the role of the surfactant of bottom ash as a viscosity reducing agent is discussed. In addition, the mechanism of interaction between fly ash particles and the surfactant has been discussed.

An efficient sensor surface is crucial in design of a carbon-based electrochemical sensing device when an ultralow and selective detection is required . Today, functional nanomaterials are synthesized and applied for sensor surface engineering to lower the limit of detection, rapid signal, and for onsite analysis results. This chapter surveys widely used materials that are applied to modify the carbon electrode. Besides, modification strategies, application in sensing, and the reported results are briefly discussed.

The surface properties of materials are very critical for their use in biomedical applications, such as biomedical implants, tissue engineering scaffolds, and other biomedical devices, including drug delivery devices. The different bioapplications are very specific in their requirement for the surface properties of materials. Polysaccharides have been extensively studied for their biomedical applications, e.g., tissue engineering scaffolds, drug delivery devices and wound healing. Various classes of polysaccharides have been employed for different bioapplications due to their structural variability, which provides the desired surface properties for specific biomedical applications. However, to improve the material properties further at the cell-material interface for various bio-applications, polysaccharides have attracted renewed interest amongst researchers due to certain advantages, such as the material of choice over other available biomaterials metallic, ceramic and polymeric either in combinations or alone. This chapter covers the advances in the use of different classes of polysaccharides in terms of their origin and their modified forms for various applications. The further discussion involves the various surface characteristics required at cell-material interfaces for biomaterials for application in tissue scaffolds. Furthermore, the discussion involves the various bioapplications of polysaccharides, focusing on applications in tissue engineering and drug delivery.

Coating is the most demanding cost-effective process for all high valued structural and functional materials. To meet the various market demands, further modification of the coating surface is highly essential. In this chapter, the additive modified metal coating has been discussed with respect to different parameters. Implementation and physibility of metal, ceramic, polymeric and organic additives on metal surface have been discussed. It is found that the additive modified coating able to enhance the wear property, the corrosion property as well as the optical property of the structure. This chapter demonstrated the surface physical and chemical properties correlated with the matrix-reinforced materials cohesiveness and compatibility with the applied area.

This chapter explores a systematic investigation of the crystal structure, microstructure, and microwave dielectric properties of Mg2TiO4 ceramics added with differentxwt%. (x = 0.5, 1.0 and 1.5 wt. %) of CeO2 nanoparticles, prepared by conventional solid-state reaction method. Since, densification of pure - Mg2TiO4 (MTO) ceramics is more than 1450 °C, which restricts its practical utility. However, enhanced densification and uniform microstructure are achieved at about 1300 °C, when CeO2 nanoparticles were added to MTO ceramics, along with improved microwave dielectric properties. The best combination of room temperature microwave dielectric properties (εr~ 14.6, Q × fo~ 167,000 GHz @ 9.5 GHz) was obtained for MTO ceramics added with 1.5 wt.% CeO2 nanoparticles, sintered at 1300 °C for 3 hours. The observed microwave dielectric properties of the MTO ceramics showed significant dependence on sintering temperature, relative density, uniform surface morphology, and the nature of additive concentrations. The proposed material has its practical utility in various microwave communication applications.

The perovskite is shown to be the single most versatile ceramic, that hasgained much more attention fromresearchersdue to a huge numberof applications. Perovskite compounds providean enormous variety of structural modifications and variants. The perovskite-type oxides exhibit both physical and biochemical characteristics. Based on Perovskite-phase metal oxides, a distinct range of properties became useful for different applications. Perovskite materials have attractive characteristics in electrical conductivity, dielectric constant, dielectric loss, structural, and magnetic properties. Perovskite materials showed efficient essential properties for photovoltaic solar cells.