The Department of Chemical Engineering

at the University of Virginia

Presents

Russell Chianelli

Department of Chemical Engineering

University of Texas—El Paso

Maya Pigments: Ancient Technology/Modern Economic Opportunity

Maya Blue is a famous blue pigment composed of palygorskite clay and indigo.  It was used by the ancient Maya and provides a dramatic background for some of the most impressive murals throughout Mesoamerica.  Despite hundreds of years of exposure in the humid climate of the Yucatan, the color of the Maya Blue pigment remains unaltered.  Chemical studies showed that Maya Blue is not destroyed in the presence of acids, alkalis, and chemical solvents.  Our earlier studies focused on authentic mural chip fragments obtained from ancient Mesoamerican murals that exhibit the presence of the Maya Blue.

The recent aim of our research has been to synthetically reproduce the pigment and to understand the clay/organic interaction that imparts to the material its remarkable beauty and stability.  Furthermore, we report that knowledge of this structure suggests new structures leading to a new family of organic/inorganic complex nano-materials with many potential applications.  Studies of the synthetic version of Maya Blue using synchrotron X-ray diffraction, surface area measurements (BET), solid-state NRM, and infrared spectroscopy indicate that indigo forms a strong surface complex with the clay.  High Resolution (ACCELRYS Corp) simulation studies also show that the indigo molecules partially replace the free water molecules in the channels of the palygorskite clay structure, creating a hybrid structure that gives the material the characteristic color and stability.  New complexes are reported including a thioindigo/palygorskite complex.  These new materials open an exciting class of novel materials.

Thursday November 13, 2008

11:00 AM, ChE 005

Refreshments served at 10:45 am in the ChE Lobby