Copper-containing resorcinol–formaldehyde networks

Abstract

The effect of copper ions on the polymerization and the structure of resorcinol–formaldehyde (RF) hydrogels, and on the resulting aerogels, is studied by a range of different techniques. Although the activation energy of the RF reaction in the presence of copper acetate is the same as with sodium carbonate, measurements by dynamic light scattering, small angle X-ray scattering, scanning electron microscopy and nitrogen adsorption reveal appreciable differences in the microscale structure and porosity of aerogels that have been synthesized with or without CuAc, before they are dried supercritically. The presence of copper ions produces a much finer mesh size on the submicron scale and increases the BET surface area of the aerogels to 2000 m/g, more than twice as much as those synthesized with sodium carbonate alone. The increase in the volume of wider pores detected by gas adsorption is even more striking. The observed effects can be attributed to the copper acetate.