GAS SEPARATION MEMBRANES BASED ON PERMSELECTIVE FILMS OF BUCKMINSTERFULLERENES

THE SELECTIVE PERMEATION OF GASES THROUGH THIN FILMS OF CARBON-60 (BUCKMINSTERFULLERENE) HAS BEEN SUGGESTED AS A POSSIBLE APPLICATION OF THIS NOVEL FORM OF CARBON. INDEED, SUBSTANTIAL DIFFERENCES HAVE BEEN DEMONSTRATED IN THE RATES OF DESORPTION OF GASES FROM CRYSTALLINE POWDERS OF C-60 AND C-70. WHEREAS VARIOUS CARBON ADSORBENTS ARE ROUTINELY USED FOR GAS SEPARATION AND CARBON-BASED PERMSELECTIVE MEMBRANES HAVE BEEN REPORTED, NO ADSORBENT OR AMORPHOUS CARBON MEMBRANE HAS THE INHERENT ADVANTAGE OF THE GEOMETRICALLY-FIXED "PORE SIZE DISTRIBUTION" CHARACTERISTIC OF FULLERENE CRYSTALS. THEREFORE, THE OPPORTUNITY EXISTS FOR HIGHLY SELECTIVE PERMEATION BEHAVIOR IF THESE MATERIALS COULD BE MADE INTO THIN FILMS ON A PRACTICAL SUBSTRATE. THE PLANNED TECHNICAL APPROACH INVOLVES FABRICATION OF FILMS OF C-60 ON INORGANIC SUPPORTS. THE FOCUS WILL BE ON A LOW-COST, SLIP CASTING TECHNIQUE THAT TAKES ADVANTAGE OF THE SOLUBILITY BEHAVIOR EXHIBITED BY FULLERENES IN SEVERAL ORGANIC SOLVENTS. THIS ORGANIC "SLIP" WILL BE APPLIED TO A MICROPOROUS LAYER OF GAMMA ALUMINA WITH ABOUT 2 NM PORES PREPARED ON COMMERCIAL CERAMIC ULTRAFILTRATION MEMBRANES. THIS GAMMA ALUMINA LAYER WILL BE APPLIED WITH TECHNIQUES PREVIOUSLY ESTABLISHED. THE RESULTING FULLERENE MEMBRANES WILL BE TESTED FOR GAS SEPARATION BEHAVIOR AND THERMAL STABILITY AT ELEVATED TEMPERATURES.