Carbon meringues obtained from flavonoid tannin

摘要

Carbon foams are versatile materials which can be prepared by different processes and from various precursors. Thus, two main families exist having either a reticulated or a cellular porous structure. Reticulated foams are based on very open, polyhedral, cells from which only struts remain. In cellular foams, cell walls exist, leading to either polyhedral or spherical cells, depending on the total porosity. Cellular carbon foams have less open structure than reticulated ones, given that their cells are connected with each others through much smaller windows [1]. Because of their different porous structures and carbon textures, RVC and CVC foams have different properties and thus different applications. Despite their excellent properties, the production of foams has some drawbacks and limitations. Thus, a new and simpler method not involving the evolution of a gas was desired. Kitchen work observation led us to the idea of producing carbon "meringues", a new kind of carbon foams made by whipping tannin solutions containing a surfactant and carbonizing the resultant liquid foams. The advantage is the extreme easiness, fastness and repeatability of the procedure, requiring less chemicals, no washing but only a curing step in an oven before pyrolysis.