Controlled Porosity of MCM-41 Obtained by Partial Blocking of Pores by Silicon Oil
M. Gorgola, P. Krasucka b, J. Goworek b and R. Zaleski a
aMaria Curie-Skłodowska University, Institute of Physics, Department of Nuclear Methods, pl. M. Curie-Skłodowskiej 1, 20-031 Lublin, Poland
bMaria Curie-Skłodowska University, Faculty of Chemistry, Department of Adsorption, pl. M. Curie-Skłodowskiej 3, 20-031 Lublin, Poland
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Partial blocking of mesopores in the ordered MCM-41 silica by DC550 silicon oil was proposed as a preparation method of the material with controlled porosity and fixed pore size. The porosity of the samples with various content of DC550 was examined with the use of low temperature nitrogen sorption and positron annihilation lifetime spectroscopy. It was shown that the oil blocks the primary pores by forming the plugs near its entrances, but also partially locates in the interparticle spaces. The comparison of the results obtained from both investigation techniques was used to make the first attempt to obtain the calibration of ortho-positronium intensity, depending on pore volume. This is necessary to improve the utility of positron annihilation lifetime spectroscopy as a porosimetric technique. The need to take the migration of positronium to larger free volume into account is discussed.

DOI: 10.12693/APhysPolA.132.1559
PACS numbers: 78.70.Bj, 36.10.Dr, 61.43.Gt, 68.43.-h