Silica sol as a nanoglue: flexible synthesis of composite aerogels
Low-density nanoscale mesoporous composites may be readily synthesized by adding a colloidal or dispersed solid to an about-to-gel silica sol. The silica sol can "glue" a range of chemically and physically diverse particles into the three-dimensional silica network formed upon gelation. If the composite gel is supercritically dried so as to maintain the high porosity of the wet gel, a composite aerogel is formed in which the nanoscopic surface and bulk properties of each component are retained in the solid composite. The volume fraction of the second solid can be varied above or below a percolation threshold to tune the transport properties of the composite aerogel and thereby design nanoscale materials for chemical, electronic, and optical applications.
Morris
CA
Surface Chemistry (Code 6170), Surface Modification (Code 6370), and Optical Techniques (Code 5670) Branches, Naval Research Laboratory (NRL), Washington, DC 20375, USA.
Anderson
ML
Stroud
RM
Merzbacher
CI
Rolison
DR