Morak Roland, Braxmeier Stephan, Ludescher Lukas, Putz Florian, Busch Sebastian, Hüsing Nicola, Reichenauer Gudrung, Paris Oskar
Institute of Physics, Montanuniversität Leoben, Franz-Josef Strasse 18, Leoben, 8700, Austria.
Bavarian Center for Applied Energy Research, Magdalene-Schoch-Strasse 3, Würzburg, 97074, Germany.
J Appl Crystallogr. 2017 Sep 14;50(Pt 5):1404-1410. doi: 10.1107/S1600576717012274. eCollection 2017 Oct 1.
A new 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 HO/DO 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 HO at large scattering vectors.
一种结合小角中子散射（SANS）和膨胀计的新装置被用于测量具有分级孔隙率的整体式二氧化硅样品的水吸附诱导变形。该样品呈现出由大孔和包含二维六方有序圆柱形介孔的支柱组成的无序骨架。使用具有零散射长度密度的HO/DO水混合物作为吸附剂，可以根据相应衍射峰的位移定量测定孔晶格应变。将这种径向支柱变形与用膨胀计同时测量的样品宏观长度变化进行比较，并基于在不同长度尺度上有效的变形机制讨论这两个量之间的差异。结果表明，通过评估大散射矢量处HO的非相干散射贡献，SANS数据还提供了一种定量确定材料吸附等温线的简便方法。
