8 Environmentally-Safe Polymer-Metal Nanocomposites with Most Favorable Distribution of Catalytically Active and Biocide Nanoparticles A. Alonso 1 , J. Macanás 2 , G.L. Davies 3 , Y.K. Gun’ko 3 , M. Muñoz 1 and D.N. Muraviev 1 1 Universitat Autònoma de Barcelona 2 Universitat Politècnica de Catalunya 3 Trinity College Dublin 1,2 Spain 3 Ireland 1. Introduction As rule of thumb, nanomaterials (NMs) possess different properties compared to the same material in its coarser or bulk form (Schulenburg, 2008). Once a material is reduced below 100 nm in size, its components begin demonstrating unusual features based on quantum mechanics, rather than macroscopic Newtonian mechanics, which influence a variety of material properties such as conductivity, heat transfer, melting temperature, optical properties, magnetization, etc. (Bhushan, 2007) . Taking advantage of these singular properties in order to develop new products (and also new synthetic procedures) is the main purpose of Nanotechnology, and that is why it is frequently regarded as ‘‘the next industrial revolution’’ (Lane, 2002; Miley et al., 2005). Although Nanoscience and Nanotechnology are quite recent disciplines, there have already been a high number of publications which discuss these topics (Ajayan et al., 2005; Blackman, 2008; Campelo et al., 2009; Giannazzo et al, 2011; Hassan, 2005; Joo, 2006; Klabunde, 2005; Li et al., 2008; Macanás et al., 2011; Nicolais & Carotenuto, 2005; Rozenberg & Tenne, 2008; Schmid, 2010; Vatta et al., 2006; Zeng, 2004). However, some important concepts are still under debate. The safety of nanomaterials is of high priority, but more fundamental ideas are also quite unclear nowadays. NMs are commonly defined as discrete objects whose size is less than 100 nm in at least one dimension (Haverkamp, 2010). Nanocomposites are known as materials which include in their composition one or more functional materials. Nanotechnology is a multidisciplinary field, as it combines the knowledge from different disciplines: chemistry, physics and biology amongst others (Klabunde, 2005; Schmid, 2006, 2010). Surface chemistry is also of great importance to the properties of NMs and nanoparticles (NPs) in particular. This is thanks to decreasing NPs size which causes their surface effects to become more significant, due to an increase in the volume fraction of surface atoms, which determines in some instances their special properties (Bowker, 2009). NPs have always been present in the www.intechopen.com