Measurement of Surface Areas for Porous and Particulate Materials

Unmet Need
Properties of a material such as catalysts or the capacity of a material to capturing toxic gases can be highly dependent on the surface area accessible by the desired molecule. In general, the more porous a material, the higher the surface area. However, the increase in surface area from making something more porous with smaller and smaller pores does not always increase the desired function once pores reach a critical size.  

The standard method for measuring the surface area of porous materials is the BET method. While the BET method works well for macroporous materials, as the size of the pores approach the microscale and smaller (50 nm and smaller), the values obtained from BET measurements are false. Due to the condensation of adsorbate molecules in the pores of these microporous materials during the BET test, the value obtained tends to be a measure of void volume or pore volume instead of surface area.
 
Technology Overview
Johns Hopkins researchers have developed a method to measure the thermodynamic adsorption capacity as opposed to the geometric capacity measured by the BET method.  This thermodynamic capacity is a measurement of how much of a given adsorbate molecule can be adsorbed at the point where the repulsions of other molecules is balanced by the attractive forces of the surface of a material. The measurements can be done using field conditions for molecule capturing materials, such as the desired molecule/temperature/pressure/etc., to give a true measurement of adsorptive capacity.
 
Stage of Development
The researchers thus far have developed the method.
 
Publications
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