Scattering from Lamellar Structure

The Mg-Al-C03-LDH used as adsorbent and sorbent was prepared with an Mg Al ratio of 2 1 by the coprecipitation method at variable pH [6], The material obtained was characterised by powder X-ray diffraction (PXRD, using a Siemens D-5005 X-ray diffractometer), and elemental and thermal analyses. The material showed the characteristic lamellar structure with a basal spacing of 7.6 A, specific surface area of 87.1 m2 g 1, determined by the N2-BET adsorption isotherm, and an approximate minimum molecular formula [Mg, MAt, (oh) m ](CO, ) 5 2.3 i(h2o) The size distribution and the average size of the LDH particles were determined by light scattering, using a Zetasizer 4 from Malvern. 

Fig. 5.4 Plot showing that the SAXS intensity from a PE-PEE diblock (M = 23 kg mol-1, /pe = 0.49) at a temperature below the PE crystallization temperature can be represented as the sum of a broad peak from amorphous and crystalline PE (dashed curve with one peak) plus the multiple Bragg peak scattering from a lamellar structure (dashed curve with four peaks) (Ryan et al. 1995).

Figure 8 Scattering curve from human SC after heating to various temperatures followed by cooling to room temperature. The temperatures to which the SC was heated are indicated, n = 1, 2, etc. refer to the orders of diffraction peaks from a lamellar structure with a Bragg spacing of 134 A. n = I, II refer to peaks corresponding to a lamellar structure with Bragg spacing of 64 A. (Data from Bouwstra et al., 1991.)...

Other well-established methods of analysis include modeling the experimental data using geometrical solid-body representations of the scattering species. This method allows for the construction of many kinds of geometrical models (e.g., hollow shells, core-shell particles, lamellar structures, etc. and provides for the interactive least-squares refinement of the dimensions of the models to fit the data. This approach has been widely used to analyze SANS data obtained from colloidal and polymeric systems. ... 

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