A colloid is a dispersion of very small particles of a substance inside another. It applies to fine smoke in air, proteins in water such as milk, nanoparticles in glass as in stained glass or in liquid solutions.
The synthesis of colloidal nanostructures is a chemical reaction that is kinetically controlled. The reaction may proceed by homogeneous nucleation or by reaction on seeds if the former can be avoided. There is a theoretical framework for nucleation and growth. In practice, recipes are still developed mostly in an empirical process. This is because many factors affecting the kinetics are not that well known. A different material can be grown on the seeds which leads to core/shell particles. The variety of shapes of crystalline materials arises from different growth rates of different facets. A predictive control of shape is not yet possible but many different shapes have been made.
Advances rely mostly on electronic microscopy tools, including the high resolution Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM) in the GCIS building.