A chemical reaction, derived from an ancient recipe for hair dyeing, is used to precipitate nanoparticles of mercury sulphide in hair by the simple process of immersion in a water solution of Ca(OH)2 and HgO.
After several days, HgS nanoparticles appear throughout the hair and are particularly numerous in the various interfaces. The formation of these nanoparticles has been studied by analytical and atomic resolution electron microscopy. High resolution quantitative analysis allowed the determination of two varieties of HgS precipitate crystal structures formed: a hexagonal cinnabar and a cubic metacinnabar structure. This very simple process of a chemical reaction in hair is a particularly inexpensive way to fabricate semiconductor sulphide nanoparticles with specific properties.
G. Patriarche, P. Walter, E. Van Elslande, J. Ayache & J. Castaing, Characteristics of HgS nanoparticles formed in hair by a chemical reaction, Philosophical Magazine 93 (1-3):137-151 (2013), DOI : 10.1080/14786435.2012.674225