Thermally-induced color transformation of hematite: insight into the prehistoric natural pigment preparation.

Since the prehistoric era, hematite has been known as a reddish color pigment on rock art, body paint, and decorating substances for objects discovered almost worldwide. Recently, studies about purple hematite used in prehistoric pigment have been done vigorously to investigate the origin of the purple pigment itself. These previous studies indicate that the differentiation of crystallinity, crystal size, morphology, and electronic structure can cause the color shift, resulting in purple hematite.

Thermodynamic Picture of Phase Segregation during the Formation of Bicontinuous Concentric Lamellar () Silica.

The thermodynamic picture describing the formation mechanism of bicontinuous concentric lamellar () nanostructured silica particles, silica, was investigated thoroughly. A series of classical kinetics of silica by varying the synthesis time were employed to observe the morphological evolution of silica. The formation mechanism of silica is proposed as the hydrolysis and condensation reactions in the reverse micelle, followed by the phase segregation process.

Further Insight into the Definite Morphology and Formation Mechanism of Mesoporous Silica KCC-1.

The unique three-dimensional pore structure of KCC-1 has attracted significant attention and has proven to be different compared to other conventional mesoporous silica such as the MCM-41 family, SBA-15, or even MSN nanoparticles. In this research, we carefully examine the morphology of KCC-1 to define more appropriate nomenclature. We also propose a formation mechanism of KCC-1 based on our experimental evidence.