Self-Assembling Siloxane Nanoparticles with Three Phases

Inorganic nanometer-sized particles (nanoparticles) are attracting attention as reinforcing fillers for use in polymer-nanoparticle composites (nanocomposites) because they improve key characteristics of these composites at a relatively low content (Hussain et al., 2006, Jordan et al., 2005). For example, clay nanoparticles (Usuki et al, 2005), metal oxide nanoparticles such as silica (Rosso et al 2006) and titania nanoparticles (Zelikman et al., 2006), and carbon nanotubes (Moniruzzaman & Winey, 2006) increase the mechanical properties, especially the elasticity modulus, of many kinds of polymer composites. However, currently available nanoparticles insufficiently improve the tenacity (elongation at breaking point) of nanocomposites, which is necessary if nanocomposites are to be used in durable products such as electronic equipments and automobiles. This is mainly because these nanoparticles lack rubber-like elasticity although they have an affinity for a polymer matrix. Adding a typical elastomer such as rubber or plasticizer (e.g., a long chain alkyl ester) with a high affinity for a polymer matrix, however, reduces the breaking strength and elasticity modulus of the composite due to their lack of rigidity (Li & Turng, 2006, Shibata et al., 2006).