Challenges in nanomaterials characterization - from definition to analysis (capítulo 1)

Nanomaterials have outstanding properties and have several applications, ranging from foods, cosmetics, pharmaceuticals to energy, construction, etc. As with all novel products, the benefits of nanomaterials use must be weighed against its health and environmental impact. They have different origins, natural, incidental, or engineered, they are widespread, and they need to be classified and characterized for various purposes, including nanotoxicology studies and risk assessment, workplaces and environment safety evaluation, consumer products evaluation, as well as manufacturing process control. To properly characterize nanomaterials, a consensual definition of nanomaterial is needed, and several analyses using the available characterization techniques must be performed. Various properties are relevant in the characterization process and many of them, namely size, are still a challenge that the research community is facing. The measurement of physical and chemical properties is very important in the case of nanomaterials. In view of this, in this chapter, available analytical techniques are reviewed based on nanomaterials classification, regulatory demands and toxicology assessment. Additionally, some of the current major challenges and gaps in nanomaterials characterization are identified and listed.