Reflections on the material science of clay minerals

Possible new applications of clay minerals are explored continuously. Three such areas are clay-polymer nanocomposites, clay mineral films and clay mineral catalysts. Advances in these areas must come from the increase of fundamental knowledge of the clay minerals, especially the expanding clay minerals or smectites. Examples of fundamental research areas are: the mechanical properties of single clay layers and the change of these mechanical properties with the number of layers in a clay mineral particle; control of the organization of clay mineral layers and of molecules in the interlayer space for the production of functional films; and the distribution of pillars and of metal nanoparticles in the interlayer space for application as catalysts. Natural clay minerals suffer from several disadvantages, such as the presence of impurities and inhomogeneities in sizes and shapes of particles and in charge distribution. Synthesis of clay minerals with well-defined sizes and shapes of the particles and with homogeneous charge distribution is imperative to obtain significant advancement of knowledge.