US EPA

2548210 

Journal Article 

AFM-porosimetry: Density and pore volume measurements of particulate materials 

Sorensen, MH; Valle-Delgado, JJ; Corkery, RW; Rutland, MW; Alberius, PC 

2008 

1 

Langmuir
ISSN: 0743-7463
EISSN: 1520-5827 

24 

13 

7024-7030 

English 

18503284 

10.1021/la800260h 

WOS:000257101100086 

We introduced the novel technique of AFM-porosimetry and applied it to measure the total pore volume of porous particles with a spherical geometry. The methodology is based on using an atomic force microscope as a balance to measure masses of individual particles. Several particles within the same batch were measured, and by plotting particle mass versus particle volume, the bulk density of the sample can be extracted from the slope of the linear fit. The pore volume is then calculated from the densities of the bulk and matrix materials, respectively. In contrast to nitrogen sorption and mercury porosimetry, this method is capable of measuring the total pore volume regardless of pore size distribution and pore connectivity. In this study, three porous samples were investigated by AFM-porosimetry: one ordered mesoporous sample and two disordered foam structures. All samples were based on a matrix of amorphous silica templated by a block copolymer, Pluronic F127, swollen to various degrees with poly(propylene glycol). In addition, the density of silica spheres without a template was measured by two independent techniques: AFM and the Archimedes principle.