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Quantifying adsorption‐induced deformation of nanoporous materials on different length scales
Author(s) -
Morak Roland,
Braxmeier Stephan,
Ludescher Lukas,
Putz Florian,
Busch Sebastian,
Hüsing Nicola,
Reichenauer Gudrung,
Paris Oskar
Publication year - 2017
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s1600576717012274
Subject(s) - nanoporous , materials science , scattering , neutron scattering , small angle neutron scattering , porosity , adsorption , deformation (meteorology) , macropore , diffraction , length scale , neutron diffraction , mesoporous material , composite material , small angle scattering , porous medium , optics , chemistry , nanotechnology , mechanics , physics , biochemistry , catalysis
A new in situ setup combining small‐angle neutron scattering (SANS) and dilatometry was used to measure water‐adsorption‐induced deformation of a monolithic silica sample with hierarchical porosity. The sample exhibits a disordered framework consisting of macropores and struts containing two‐dimensional hexagonally ordered cylindrical mesopores. The use of an H 2 O/D 2 O water mixture with zero scattering length density as an adsorptive allows a quantitative determination of the pore lattice strain from the shift of the corresponding diffraction peak. This radial strut deformation is compared with the simultaneously measured macroscopic length change of the sample with dilatometry, and differences between the two quantities are discussed on the basis of the deformation mechanisms effective at the different length scales. It is demonstrated that the SANS data also provide a facile way to quantitatively determine the adsorption isotherm of the material by evaluating the incoherent scattering contribution of H 2 O at large scattering vectors.