TY - JOUR
T1 - Extracting the pore size distribution of compliant materials from nitrogen adsorption
AU - Reichenauer, G.
AU - Scherer, G. W.
N1 - Funding Information:
This work was supported by DOE contract DEFG 02-97ER4. The authors would like to thank Martin Glora and Thomas Schliermann, Würzburg University, for performing the SAXS measurements.
PY - 2001/8/31
Y1 - 2001/8/31
N2 - Adsorption of nitrogen at 77.4 K is a well-established technique for the characterization of mesopores. However, this method has been questioned in the case of compliant materials, as the capillary pressures upon sorption can be as large as several MPa's and thus high deformations are expected upon analysis. Simultaneous recording of nitrogen sorption data and linear length changes for silica aerogels, a class of highly porous, compliant materials, reveals a new type of isotherm, that is characteristic for compliant materials in general. Comparison of dilatation and sorption data shows that the bulk modulus of a compliant material can be calculated from its nitrogen sorption isotherm alone. Using this information together with a model that describes the relationship between macroscopic deformation and changes in pore size and volume, the isotherm can be corrected for the contraction of the sample during analysis. The corresponding pore size distribution is found to be in excellent agreement with results deduced from small angle X-ray scattering.
AB - Adsorption of nitrogen at 77.4 K is a well-established technique for the characterization of mesopores. However, this method has been questioned in the case of compliant materials, as the capillary pressures upon sorption can be as large as several MPa's and thus high deformations are expected upon analysis. Simultaneous recording of nitrogen sorption data and linear length changes for silica aerogels, a class of highly porous, compliant materials, reveals a new type of isotherm, that is characteristic for compliant materials in general. Comparison of dilatation and sorption data shows that the bulk modulus of a compliant material can be calculated from its nitrogen sorption isotherm alone. Using this information together with a model that describes the relationship between macroscopic deformation and changes in pore size and volume, the isotherm can be corrected for the contraction of the sample during analysis. The corresponding pore size distribution is found to be in excellent agreement with results deduced from small angle X-ray scattering.
KW - Adsorption
KW - Aerogel
KW - Capillary condensation
KW - Compliant porous material
KW - Pore size distribution
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U2 - 10.1016/S0927-7757(01)00619-7
DO - 10.1016/S0927-7757(01)00619-7
M3 - Article
AN - SCOPUS:0035979926
SN - 0927-7757
VL - 187-188
SP - 41
EP - 50
JO - Colloids and Surfaces A: Physicochemical and Engineering Aspects
JF - Colloids and Surfaces A: Physicochemical and Engineering Aspects
ER -