Photochemically Implemented Metal/Polymer Nanocomposite Materials for Advanced Optical Applications

Nanocomposite materials metal/polymer combines together the properties of several components. Nowadays, they are regarded as promising systems for advanced functional applications (Armelao et al., 2006). In view of this, the incorporation of nanoparticles into polymer has opened the way to a new generation of materials exhibiting unique electrical, optical, or mechanical properties which make them attractive for applications in areas like optics (Jin et al., 2001; Ung et al., 2001), photoimaging and patterning (Tizazu et al., 2009; Stranik et al., 2010), sensor design (Shenhar and Rotello, 2003), catalysis (Vriezema et al., 2005), and as antimicrobial coatings (Aymonier et al., 2002; Sondi and Salopek-Sondi, 2004). Research in novel methods to prepare metal nanocomposite materials has been greatly stimulated due to their attractive properties and promising applications. One of the main interests of metal nanoparticles stems from their unique physical properties which can be addressed by the chemical control of their shape and size (El-Sayed, 2001; Eustis and ElSayed, 2006). Amongst them, gold, silver and cooper with nanometer size, have been the focus of great interest because these nanoparticles exhibit a very intense absorption band in the visible region due to their surface plasmon resonance. Metal/polymer nanocomposites can be prepared by two approaches. The first one involves metal nanoparticles dispersion in a polymerizable formulation, or in a polymer matrix. In this case, the reduction of metal ions and polymerization occur successively hence the aggregation of nanoparticles that makes this synthetic procedure often problematical. In the second approach, nanoparticles are generated in situ during the polymerization to avoid agglomeration. The polymerization reaction and the synthesis of nanoparticles that proceed simultaneously were the subject of extensive studies. Another technique consists in polymerizing the matrix around a metal nanocore by using chemically compatible ligands (Mandal et al., 2002) or polymeric structures (Corbierre et al., 2001). In all cases, the high-performance of nanomaterials depends on the controlled distribution of uniformly shaped and sized particles. Therefore, the development of synthetic strategies to control particles growth and/or agglomeration during nanocomposite fabrication appears quite obviously as a key challenge. Photochemical reduction by irradiating a dye sensitizer in the presence of metal ions provides a convenient way to produce nanoparticles embedded in polymer (Balan et al.,