Sample environments and techniques combined with Small Angle X-ray Scattering

Bras, Wim; Ryan, Anthony J.

doi:10.1016/s0001-8686(97)00032-8

Cited by 47 publications

(32 citation statements)

References 102 publications

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“…That can be an evolution in time, temperature, pH, concentration, etc. Only a certain range of t can be measured, and therefore, a dynamical spectrum is implemented as (1) where y(ν) is a reference spectrum of the system. An average spectrum is usually picked as a reference spectrum, but any reasonable spectrum can be chosen.…”

Section: Methodsmentioning

confidence: 99%

Combined SAXS/UV–vis/Raman as a Diagnostic and Structure Resolving Tool in Materials and Life Sciences Applications

2014

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In order to diagnose and fully correlate structural, chemical, and functional features of macromolecules and particles in solution, we propose the integration of spectroscopy and scattering on the same measuring volume and at the same time in a dedicated sample environment with multiple probes. Combined SAXS/UV-vis and SAXS/Raman information are employed to study the radiation damage effect in proteins in solution and the scattering from single wall carbon nanotubes (SWNTs) in SDS dispersion, respectively. In the first case, a clear correlation is observed between the time dependence of the radius of gyration (Rg) of the protein determined by SAXS and the turbidity of the protein solution extracted from simultaneous UV-vis measurements. In the second case, the ratio of bundled/isolated carbon nanotubes is obtained unambiguously through proper modeling of the scattering data and cross-validated with the Raman information. The uses of convex constraint analysis (CCA) and two-dimensional correlation analyses (2DCOS and 2DHCOS) are introduced to fully explore the combination of data sets from different techniques and to extract unique insights from the sample.

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Section: Methodsmentioning

confidence: 99%

Combined SAXS/UV–vis/Raman as a Diagnostic and Structure Resolving Tool in Materials and Life Sciences Applications

2014

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“…PDF analysis is a method of extracting structure-related information from SAXS and WAXS data and the evaluation takes into account both the Bragg (in non-dilute systems) as well as diffuse scattering (in dilute systems, related to short-range order effects). This sensitivity to the local structure has made the PDF analysis the tool of choice for structural studies of amorphous materials (e.g., Glatter, 1992;Bras and Ryan, 1998 and references therein). The scattering length distribution function p(r), which is equal to the total scattering length of the atoms per unit volume of matrix are shown for various particle shapes in a Fig.…”

Section: Basic Conceptsmentioning

confidence: 99%

“…We refer the reader to several books or review papers that detail the basics of the SAXS/WAXS theory (e.g., Guinier, 1939;Guinier and Fournet, 1955;Glatter and Kratky, 1982;Glatter, 1992;Bras et al, 1993;Bras and Ryan, 1998). Only in the last decade have SAXS and WAXS been also applied to geological or environmental problems and a recent review applied to geomedia is discussed in Waychunas (2001) and Waychunas et al (2001).…”

Section: General Introduction and Basic Conceptsmentioning

confidence: 99%

Nucleation, Growth, and Aggregation of Mineral Phases: Mechanisms and Kinetic Controls

Benning

Waychunas

2008

Kinetics of Water-Rock Interaction

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The formation of any phase, whether natural or synthetic (Fig. 7.1), is usually a disequilibrium process that follows a series of steps until a thermodynamically stable state (equilibrium) is achieved. The first step in the process of creating a new solid phase from a supersaturated solution (either aqueous or solid) is called nucleation. A particle formed by the event of nucleation usually has a poorly ordered and often highly hydrated structure. This particle is metastable with respect to ordering into a well-defined phase, which can accompany growth of the particle. This process of initiation of a new phase is defined as a first order transition and can follow various pathways involving a host of mechanisms. One of these pathways occurs when individual nuclei coalesce into larger clusters, a process defined as aggregation, which itself can follow a series of different pathways. The new phase is thermodynamically defined when the growing nucleus or aggregate has distinct properties relative to its host matrix; for example, a well-defined crystal structure, composition and/or density. These processes depend on a plethora of chemical and physical parameters that control and strongly affect the formation of new nuclei, the growth of a new crystal, or the aggregation behavior of clusters, and it is these issues that will be the focus of this chapter. We will discuss the mechanisms and rates of each process as well as the methods of quantification or modeling from the point of view of existing theoretical understanding. Each step will be illustrated with natural examples or laboratory experimental quantifications. Complementary to the information in this chapter, a detailed analysis of the mechanisms and processes that govern dissolution of a phase are discussed in detail in Chap. 5 and more detailed information about molecular modeling approaches are outlined in Chap. 2.

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“…18,[38][39][40][41][42][43][44] Although SAXS has been an important tool to understand various mechanisms already for a long time, e.g. by providing insights in the mechanism of phase transitions and structure development of soft matter, [45][46][47][48][49][50][51] and in situ SAXS and grazing incidence small angle X-ray scattering (GISAXS) experiments were conducted to investigate the kinetics of structure formation during isoporous flat sheet membrane fabrication for the commonly used block copolymer solutions, [52][53][54][55] the structure formation in block copolymer HFM has not been probed by in situ characterization techniques.…”

Section: Introductionmentioning

confidence: 99%

Self-assembly of block copolymers during hollow fiber spinning: anin situsmall-angle X-ray scattering study

et al. 2019

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We investigated the self-assembly of block copolymers during hollow fiber membrane (HFM) fabrication by conducting in situ small angle X-ray scattering (SAXS) and ex situ scanning electron microscopy (SEM) studies. SAXS enables us to follow the structural rearrangements after extrusion at different distances from the spinning nozzle. The kinetics of the spinning process is examined as a function of the composition of block copolymer solutions and the spinning parameters. We studied the influence of the extrusion rate on the block copolymer microdomains and their self-assembly in weakly segregated and ordered solutions. The addition of magnesium acetate (MgAc2) leads to ordering of micelles in the block copolymer solution already at lower polymer concentrations and shows an increased number of micelles with larger domain spacing as compared to the pristine solution. The SAXS data show the effect of shear within the spinneret on the self-assembly of block copolymers and the kinetics of phase separation after extrusion.It is observed that the ordering of micelles in solutions is decreased as indicated by the loss of crystallinity while high extrusion rates orient the structures perpendicular to the fiber direction. The structural features obtained from in situ SAXS experiments are correlated to the structure in the block copolymer solutions in absence of shear and the morphologies in flat sheet and HF membranes obtained by ex situ SEM. This allows a systematic and comparative study of the effects varying the microdomain ordering within different block copolymer solutions and the formed membrane structures. KEYWORDS:block copolymer, self-assembly, in situ SAXS, isoporous membrane, isoporous hollow fiber membrane Highlight of work:Study of the self-assembly of block copolymers in ordered and weakly segregated solutions after extrusion during fabrication of isoporous hollow fiber membranes. Graphical Abstract/TOC

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Sample environments and techniques combined with Small Angle X-ray Scattering

Cited by 47 publications

References 102 publications

Combined SAXS/UV–vis/Raman as a Diagnostic and Structure Resolving Tool in Materials and Life Sciences Applications

Combined SAXS/UV–vis/Raman as a Diagnostic and Structure Resolving Tool in Materials and Life Sciences Applications

Nucleation, Growth, and Aggregation of Mineral Phases: Mechanisms and Kinetic Controls

Self-assembly of block copolymers during hollow fiber spinning: anin situsmall-angle X-ray scattering study

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