Table of contents

The XIV International Conference on Small-Angle Scattering, SAS-2009, was held in Oxford UK, 13–18 September 2009, and was jointly organised under the auspices of the International Union of Crystallography Commission on SAS by a team from the Diamond Light Source and the ISIS Pulsed Neutron Source – their first such joint venture – with help from the UK Science and Technology Facilities Council. It was the first time that this long running and successful series of conferences on the application, science and technology of small-angle scattering techniques had been staged in the UK.

The UK has a proud heritage in small-angle scattering: as home to one of the world's first SANS instruments (at AERE Harwell), as the site of the world's first 2nd generation X-ray Synchrotron (the SRS at Daresbury with its suite of SAXS beamlines), and latterly as the location of the world's most successful pulsed source SANS instrument. Indeed, 2009 also marked the 25th Anniversary of neutron operations at ISIS and the opening of a Second Target Station. Whilst the SRS ceased operations in 2008, its mantle has been inherited by the Diamond synchrotron. Many delegates took the opportunity to visit both Diamond and ISIS during a conference excursion.

Despite the prevailing global economic downturn, we were delighted that 434 delegates from 32 different countries were able to attend SAS-2009; two-thirds were drawn from the UK, Germany, Japan, the USA and France, but there were also sizeable contingents from Australia, Korea, Taiwan and South America. In many ways this geographical spread reflects the present and emerging distribution, respectively, of 3rd generation X-ray synchrotrons and high-flux neutron sources, although the scope of the conference was not solely limited to these probes.

Financial support from the IUCr enabled us to grant bursaries to attend SAS-2009 to 12 delegates from emerging countries (Algeria, Argentina, Brazil, India, Nepal, Romania, Russia and the Ukraine).

The scientific heart of the conference comprised 10 plenary sessions, interspersed by 39 'themed' parallel sessions, 2 poster sessions, an afternoon tour of Diamond and ISIS, and a week-long exhibition. There were 144 contributed oral presentations and 308 poster presentations across a total of 21 themes. Over half of all presentations fell under 6 themes: biological systems, colloids and solutions, instrumentation, kinetic and time-resolved measurements, polymers, and surfaces and interfaces. The importance of SAS techniques to the study of biology, materials science and soft matter/nanoscience is clear.

The plenary presentations, which covered topics as diverse as advanced analysis techniques, biology, green chemistry, materials science and surfaces, were delivered by Frank Bates, Minnesota, USA, Peter Fratzl, MPI Golm, Germany, Buxing Han, Bejing, China, Julia Kornfield, CIT, USA, Jan Skov Pedersen, Aarhus, Denmark, Moonhor Ree, Pohang, Korea, Mitsuhiro Shibayama, Tokyo, Japan, Robert Thomas, Oxford, UK, Jill Trewhella, Sydney, Australia, and Thomas Zemb, ICSM Bagnols, France.

Instigated by representatives of the Belgian and Dutch SAS communities one parallel session was dedicated to a tribute for Michel Koch, the pioneer of so many novel applications of SAXS, who retired after 30 years at the EMBL Hamburg in late 2006. With a supporting cast that included Wim Bras, ESRF, France, Tony Ryan, Sheffield, UK and Joe Zaccai, ILL,France, and watched by former colleague André Gabriel, Michel treated the audience to a fascinating – and at times light-hearted – retrospective of the evolution of synchrotron SAXS.

Another parallel session was devoted to the work of the canSAS (Collective Action for Nomadic Small-Angle Scatterers) network of large-facility representatives and instrument scientists in areas such as data file formats, intensity calibration and software development. For further information see http://www.smallangles.net/wgwiki/index.php/canSAS_Working_Groups.

A total of nine awards were presented at the conference. The Lifetime Achievement, or 'Andre Guinier', Award, given to those who have made a sustained and recognised contribution to the development or application of Small-Angle Scattering, went to Vittorio Luzzati, Emeritus Research Scientist at the Centre de Génétique Moléculaire du CNRS, France. Dr Luzzati has had a long and distinguished career in X-ray scattering publishing over 170 research papers – 10 in Nature – which have so far accumulated over 3500 citations.

The award for 'Excellence in SAS Technical/Instrumental Development' went to J Polte, BAM, Germany, for 'New insights into nucleation and growth processes of gold nanoparticles derived via coupled in-situ methods'. That for 'Excellence in the Theoretical Development of SAS' went to C Gommes, Liege, Belgium, for 'SAXS Data Analysis of Ordered and Disordered Morphologies with Gaussian Random Field Models'. B Pauw, Technical University, Denmark, received the award for 'Excellence in the Application of SAS' for work on 'Strain-induced Internal Fibrillation of Aramid Filaments'. And the award for 'Excellence in the Communication of SAS Science' went to J G Grossmann, Liverpool, UK, for his talk on 'Probing the Structure of Biological Macromolecules in the Gas Phase'.

A Hexemer, LBNL, USA, won the prize for the 'Best Poster in Technical/Instrumental Development' for 'SAXS/WAXS using a Multilayer Monochromator'. The prize for 'Best Poster in Theoretical Development' went to S Haas, Helmholtz Centre Berlin, Germany, for 'Simultaneous structure and chemical nano-analysis of an efficient frequency upconversion glass-ceramic by ASAXS'. And in a remarkable 'double', the prizes for 'Best Poster for Application in Life Sciences' and 'Best Poster for Application in Physical Sciences' went to A Maerten and J Prass, respectively, both from MPI Golm, Germany, for their work on 'SAXS studies of human tooth dentine: analysis of a spatially inhomogeneous and varying bio-material' and 'Analysis of sorption strains in ordered mesoporous materials by in-situ small-angle x-ray diffraction'.

The conference could not have been staged without the support and commitment of a large number of people and organizations, many of whom are listed separately within these Proceedings, and it is only right that we acknowledge their contribution. The generous financial support from our sponsors was particularly welcome given the economic climate. To all of them we offer our heartfelt and grateful thanks.

We would also like to thank our Guest Editor, Goran Ungar, his team of Section Editors, and the several dozen anonymous referees, for so admirably managing the scientific review of the manuscripts in these Proceedings, and Graham Douglas and Johanna Schwarz at IoP Publishing for their assistance in bringing these Proceedings to fruition.

Stephen King Nicholas Terrill SAS-2009 Co-Chairmen and Local Organisers

SAS-2012 will be held in Sydney, Australia, 18–23 November 2012.

There are 52 papers in these Proceedings. The papers are divided into 10 thematic sections and a section for invited papers and reviews. The sections and the respective section editors are given below.

We are grateful to all section editors and the many anonymous referees for their invaluable effort which made the publication of the Proceedings possible. The refereeing process was strict and thorough, some papers were rejected and most were improved. The resulting compendium gives a good overview of recent developments in small-angle X-ray and neutron scattering theory, application, methods of analysis and instrumentation. Thus it should be a useful source of reference for a number of years to come. The papers are a good reflection of the material presented at the meeting. Because of the general high quality of the articles, it was difficult to decide which to highlight and be fair to all contributors. The following in particular have caught the attention of the editors.

Highlighted papers A statistical survey of publications reporting the application of SAXS and SANS by Aldo Craievich (paper 012003) is recommended reading for anyone needing convincing about the vibrancy of this scientific field and the ever expanding use of these techniques. Two aspects of coherent X-ray scattering, made available by the advent of the 3rd generation synchrotron sources, are discussed in the papers by Felisa Berenguer and the Diamond/UCL team (012004) and by Birgit Fischer and the DESY/Rostock team (012026). The former describe their effort to reconstruct the image of wet collagen tissue from the speckled pattern of a narrow transmitted beam and complement the results of imaging by scanning SAXS. Fischer et al. utilize the coherence of the X-ray beam in the photon correlation spectroscopy mode to determine the dynamic structure factor, from which the q-dependence of the relaxation times was determined for solutions of charged colloidal particles. The nature of particle motion was thus determined, i.e. ballistic at lower concentrations vs. restricted by 'caging' at higher concentrations. The use of scanning microbeam diffraction was also described in the paper by the group of Peter Fratzl (012031), who combined it with tilting the sample in order to obtain what is referred to as 3D SAXS. In this way the orientation distribution of crystallites in callus tissue during bone fracture healing can be explored. Naoto Yagi et al. (012024) used microbeam SAXS and WAXS to study dental enamel crystals in a caries lesion.

Anomalous, or resonant, X-ray scattering at low angles (ASAXS) was employed by Guenter Goerigk and Norbert Mattern (Jülich/Dresden) (012022) to study phase separation in the ternary alloy Ni-Nb-Y. Experiments were performed near the K-absorption edges of the three elements and the authors describe how they determined quantitatively the chemical composition of the different separate phases as well as short-range concentration fluctuations during spinodal decomposition. For organic materials, where heavy atoms are not present, typically sulphur would be replaced by Se, so ASAXS could be performed near the Se K-edge. However, Masashi Handa et al. from the University of Tokyo report in paper 012006 a feasibility study of using sulphur itself as the label. They deal with the challenging task of using low-energy X-rays at the sulphur K-edge.

Alexandra Vasilieva and teams from St Petersburg and Moscow describe in paper 012029 a study of a FCC/HCP photonic crystal with a unit cell of 650 nm using the DUBBLE beamline at ESRF, where the incident beam is focused with a compound Berilium lens to give divergence in the microradian range. Defects, correlation lengths, mosaic spread and twinning could be studied in a thin film. The use of grazing incidence small- and intermediate-angle X-ray scattering (GISAXS) was illustrated on several examples of complex liquid crystal phases and nanoparticle systems by Xiangbing Zeng and the team from Sheffield in paper 012032. Apart from the intrinsic interest in the structure of thin films of these materials, the close proximity of the surface imposes usually a very high degree of preferred orientation, facilitating structural analysis.

From the papers describing the use of neutron scattering, we highlight the study by Léon van Heijkamp and the Delft group, paper 012016, which describes proof-of-principle experiments using spin-echo SANS (SESANS) for the study of D2O-labeled liposomes and their destruction with a view of providing a nondestructive technique for monitoring targeted drug delivery for the destruction of tumor tissue. This technique is based on monitoring the decay of spin polarization of scattered neutrons, and it can probe correlation lengths from nanometres to tens of microns.

In paper 012002 Thomas Zemb discusses the various ways in which SAXS and SANS data can be combined to investigate microemulsions of surfactants lacking long-range order. Thus, for example, it is described how form and structure factors can be separated, or how the degree of connectivity can be determined between rod-like entities forming 'molten cubic' or 'sponge' phases.

In the Theory, Data Processing and Modelling section we highlight two papers. Paper 012012, by Carlos Cabrillo and co-workers from Madrid, presents a real-space model for powder samples of relatively highly ordered colloidal particles based on the radial pair distance distribution function. The model takes account of different types of disorder, i.e. of both 1st ('thermal') and 2nd ('paracrystalline') kind, as well as finite size, stacking and orientational disorder. In paper 012014 Salvino Ciccariello works out the 3D correlation function of plane objects, specifically a triangle of a general shape. This paves the way to analysing morphologies that can be approximated by cylinders of different cross-sections.

Papers 012051 (Polte et al.) and 012047 (Bras et al.) report the use of SAS in combination with X-ray spectroscopy. Ristic et al. describe a real-time study of crystal nucleation induced by ultrasound (012049), while Marianne Imperor-Clerc et al. present an investigation of lyotropic liquid crystals under shear (012052). In the Polymers section Geoff Mitchell describes modelling of SANS data on electrospun fibres (012042), while Cabral et al. describes a study of nanoparticle aggregation in bulk and thin polymer films (012046). Work on phospholipid membranes was reported by Spinozzi et al. and by Onai et al. in papers 012019 and 012018, respectively. The latter deals with the effect of osmotic pressure on model 'lipid rafts', these being considered as having an important role in the function of the mammalian cell membrane. Readers interested in biological systems will find a number of other interesting papers describing the use of either SAXS or SANS in the Biological Systems and Membranes section. A number of descriptions of recent designs of SAXS (synchrotron) and SANS beamlines, as well as detector developments can be found in the section on Beamlines and Instrumentation.

Goran Ungar, Editor-in-Chief Richard Heenan, Deputy Editor-in-Chief

All papers published in this volume of Journal of Physics: Conference Series have been peer reviewed through processes administered by the proceedings Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

A brief overview is given of the development of instruments and methods for synchrotron radiation small angle scattering and diffraction on biological systems and synthetic polymers. It is shown that many of the developments were largely accidental and although there were a number of innovations, in most cases other fields provided the sources of novelty.

We review the information gained when studying the same sample containing surfactants by SANS and SAXS. Specific information can be obtained if intensities I(q) are determined and used on absolute scale as well as over a large q-window, thus extending to the «Porod limit» asymptotic range. Comparing SAXS and SANS peak positions (when present) allows unambiguous identification of structure factors separated from underlying form factors. Absolute scale refers to scattering cross-section while resolution relates to the q_max/q_min ratio. Taking into account "external" knowledge of molecular volumes in constrained fitting from explicit models gives better results on aggregation numbers as well as on interfacial thickness than considering only Patterson functions.

We assemble in this review results on adsorption isotherms on surfactant films as well as equations of state, quantifying colloidal interactions. Identification of the topological origin of swelling behaviour are made possible by using combined SAXS and SANS on the largest possible q-range. Best results using this general methodology up to now were obtained by considering data separated from background up to q_max= 0.6 Å⁻¹ − 0.8 Å⁻¹.

We present and discuss here numerical information derived from a systematic searching of scientific papers related to SAXS and SANS published in indexed journals – from 1945 until nowadays – recorded by the Web of Science Data Bank (WoS). We have detected interesting features regarding the time dependence of the number of papers/year, N(t), indicating the existence of three well-defined periods of historical evolution with rather well-defined boundaries. All three periods exhibit a positive and approximately linear variation of N(t) but, at the two transitions between periods, the rate of growth exhibits clear and strong increases. Differences of the historical evolutions in the numbers of papers/year related to SAXS and to SANS were established. The different behaviours regarding the numbers of papers/year related to SAXS and to SANS and the existence of three different and well defined periods for N(t) can be qualitatively understood as a consequence of the progressive and increasing availability along the last three decades of very brilliant synchrotrons, last generation commercial X-ray sources, new neutron facilities, powerful computers and novel theoretical approaches for SAS data analysis. The rates of growth in the number of papers/year published by authors from a set of different countries are approximately constant along the last two decades. For other countries we have detected a slowing down effect in the number of papers/year while a clear acceleration could be noticed for the production of SAS papers by authors from several emerging countries. These opposite trends compensate in such a way that the number of SAS (SAXS+SAXS) articles published per year all around the world maintained a vigorous linear growth – during more than 20 years – at a constant rate of 60 papers/year, without any indication of eventual saturation. The observed distribution of articles among different journals indicates that a very high fraction of the volume of SAS research is focused to the structure of soft matter.

Third generation x-ray sources offer unique possibilities for exploiting coherence in the study of materials. New insights in the structure and dynamics of soft condensed matter and biological samples can be obtained by coherent x-ray diffraction (CXD). However, the experimental procedures for applying these methods to collagen tissues are still under development. We present here an investigation for the optimal procedure in order to obtain high quality CXD data from collagen tissues. Sample handling and preparation and adequate coherence defining apertures are among the more relevant factors to take into account. The impact of the results is also discussed, in particular in comparison with the information that can be extracted from conventional scanning small angle x-ray scattering (SAXS). Images of collagen tissues obtained by CXD reconstructions will give additional information about the local structure with higher resolution and will complement scanning SAXS images.

Absolute calibration of small-angle scattering data (in units of differential cross-section per unit sample volume per unit solid angle) is necessary for the determination of molecular weights, the number density of particles, the scattering-length densities of phases in multiphased systems, volume fraction, the specific surface area of the scatterers and to restrict the parameters of a given model to the set which reproduces the observed intensity. It is also a useful means for the detection of artefacts in SAS experiments. Absolute intensities from the same sample also allows intercalibration among different instruments. This work details the absolute calibration procedure of a small-angle X-ray scattering instrument, the Rigaku S-Max3000. Absolute calibration is achieved by using two standards: homogeneous and stable glassy carbon and water. The scattering intensity of glassy carbon is calibrated by comparison with the absolute-calibration measurements taken on the USAXS instrument located at the 32ID beamline of the Advanced Photon Source in Argonne National Laboratory. This instrument has primary calibration capability. Scattering from water is angle-independent and only depends on the physical property of isothermal compressibility. Absolute calibrations using two standards were compared. The agreement of scale factors obtained using two standards suggests that precalibrated glassy carbon can serve as a convenient standard for all types of materials under study.

Anomalous small-angle X-ray scattering (ASAXS) is expected to be a powerful and vital tool for the structural study of soft matter. We investigated feasibility of ASAXS near sulphur K absorption edge at SPring-8. Scattering pattern was successfully obtained and the dependence of scattering intensity on the energy of X-ray well agreed with the calculated one. This study can be the basis of structural study of soft matter using ASAXS, especially non-crystalline/amorphous materials.

We discuss the construction of a new SAXS/WAXS beamline at the Advanced Light Source at Lawrence Berkeley Laboratory. The beamline is equipped with a multilayer monochromator in order to obtain a high X-ray flux. The detrimental effects that the increased bandwidth transmitted by this monochromator could have on the data quality of the SAXS and WAXS patterns is shown to be negligible for the experimental program intended to be operated on this beamline.

Hybrid pixel detectors consisting of an array of silicon photodiodes bump-bonded to CMOS read-out chips provide high signal-to-noise ratio and high dynamic range compared to CCD-based detectors and Image Plates. These detector features are important for SAXS experiments where a wide range of intensities are present in the images. For time resolved SAXS experiments, high frame rates are compulsory. The latest CMOS read-out chip developed by the MEDIPIX collaboration provides high frame rate and continuous acquisition mode. A read-out system for an array of MEDIPIX3 sensors is under development at Diamond Light Source. This system will support a full resolution frame rate of 1 kHz at a pixel counter depth of 12-bit and a frame rate of 30 kHz at a counter depth of 1 bit. Details concerning system design and MEDIPIX sensors characterization are presented.

The new bio-SAXS beamline (ID14-3 at the ESRF, Grenoble, France) is dedicated exclusively to small-angle scattering experiments of biological macromolecules in solution and has been in user operation since November 2008. Originally a protein crystallography beamline, ID14-3 was refurbished, still as a part of the ESRF Structural Biology group, with the main aim to provide a facility with 'quick and easy' access to satisfy rapidly growing demands from crystallographers, biochemists and structural biologists. The beamline allows manual and automatic sample loading/unloading, data collection, processing (conversion of a 2D image to a normalized 1D X-ray scattering profile) and analysis. The users obtain on-line standard data concerning the size (radius of gyration, maximum dimension and volume) and molecular weight of samples which allow on-the fly ab-inito shape reconstruction in order to provide feedback enabling the data collection strategies to be optimized. Automation of sample loading is incorporated on the beamline using a device constructed in collaboration between the EMBL (Grenoble and Hamburg outstations) and the ESRF. Semi/automated data analysis is implemented following the model of the SAXS facility at X33, EMBL Hamburg. This paper describes the bio-SAXS beamline and set-up characteristics together with the examples of user data obtained.

The 36 meter small-angle neutron scattering (SANS) spectrometer BATAN (SMARTer) in Serpong, Indonesia has been revitalised for several years. The work on replacing, upgrading and improving the control system and the experimental method were conducted in order to setup the spectrometer back in operation. Two main personal computers, one for handling and controlling the mechanical system and another one for acquiring neutron data were employed at the spectrometer. The standard and established SANS data reduction and analysis programs, such as GRASP and NIST Igor have been implemented to subtract the raw scattered neutron data with the backgrounds and then analyse the corrected data. The scattering data of ferrofluids samples, Fe₃O₄ and MnZnFe₂O₄ have been obtained using SANS spectrometers in BATAN Serpong, Indonesia and HANARO-KAERI, Republic of Korea for inter-laboratory comparison and investigation of proposed research interest. The results were comparable from both scattering data analysis.

Setting out from the results found in a set of small-angle neutron scattering (SANS) experiments for neutron-irradiated Fe-Cu model alloys, a rate theory model for the simulation of the irradiation-induced time-evolution of Cu-rich precipitates in these model alloys is presented which follows the idea that the precipitate clusters are mixed Cu-vacancy aggregates. This is done by explicitly allowing the defect clusters to absorb vacancies. The resulting Vacancy-Coupled Copper Clustering (V3C) model is calibrated by SANS experiments on two different Fe-Cu model alloys neutron-irradiated at four different doses. Quantitative agreement with the SANS experiments could be achieved by introducing a dependence of the Fe-Cu interface energy on the amount of vacancies in the mixed precipitate clusters. Phenomenologically, this energy can be seen as a function of the weight-percentage of Cu in the iron matrix. An empirical expression for this dependence is suggested. In addition, the new V3C model is used to gain some preliminary insight into the time-evolution of the chemical composition of the mixed Cu-vacancy clusters, confirming qualitatively the experimental findings. The relation of our ansatz to the heterogeneous Cu-precipitation mechanism proposed by others for neutron-irradiated Fe-Cu alloys of low Cu content is discussed.

Recent advances in self-organized 3D ordered structures of submicron particles as colloidal crystals demand a precise quantitative characterization of the produced nano-structures. Small angle scattering is the technique of choice for such a task but a comprehensive quantitative modeling of the measurements is far from being straightforward. We have developed a theory based in the pair distances distribution which take into the account orientational, positional and staking disorder as well as finite size effects. We show also how the radial scattering length density of the constituent particles, essential for a comprehensive modeling of the experimental data, can be estimated from the position of the form factor local minima. The results reduce to sums of analytical functions over the distribution of pair distances and as such, are suitable for easy (automatic) parallelization.

The new generation of neutron scattering instruments being built are higher resolution and produce one or more orders of magnitude larger data than the previous generation of instruments. For instance, we have grown out of being able to perform some important tasks with our laptops. The data sizes are too big and the computational time would be too long. These large datasets can be problematic as facility users now begin to struggle with many of the same issues faced by more established computing communities. These issues include data access, management, and movement, data format standards, distributed computing, and collaboration with others. The Neutron Science Portal has been designed, and implemented to provide users with an easy-to-use interface for managing and processing data, while also keeping an eye on meeting modern computer security requirements that are currently being imposed on institutions. Users can browse or search for data which they are allowed to see, run data reduction and analysis applications, perform sample activation calculations and perform McStas simulations. Collaboration is facilitated by providing users a read/writeable common area, shared across all experiment team members. The portal currently has over 370 registered users; almost 7TB of experiment and user data, approximately 1,000,000 files cataloged, and had almost 10,000 unique visits last year. Future directions for enhancing portal robustness include examining how to mirror data and portal services, better facilitation of collaborations via virtual organizations, enhancing disconnected service via "thick client" applications, and better inter-facility connectivity to support cross-cutting research.

The knowledge of the isotropic correlation function of a plane figure is useful to determine the correlation function of the cylinders having the plane figure as right-section and a given height as well as to analyze the out of plane intensity collected in grazing incidence small-angle scattering from a film formed by a particulate collection of these cylinders. The correlation function of plane polygons can always be determined in closed algebraic form. Here we report its analytic expression for the case of a triangle. The expressions take four different forms that depend on the relative order among the sides and the heights of the triangle.

We discuss different spherically symmetric and anisotropic form factor models and test them against high resolution synchrotron based small-angle x-ray scattering (SAXS) data from synaptic vesicles (SVs), isolated from rat brain. Anisotropy of the model form factors is found to be a key ingredient for the description of the native synaptic vesicle structure. We describe changes in structural parameters due to protease digestion of SVs, and present SAXS data of SVs recorded under different pH conditions.

Two types of liposomes, commonly used in drug delivery studies, and E. coli bacteria, all prepared in H₂O, were resuspended in D₂O and measured with Small Angle Spin-Echo Neutron Scattering (SESANS). Modeling was performed using correlation functions for solid spheres and hollow spheres. The signal strength and curve shape were more indicative of hollow particles, indicating that the H₂O-D₂O exchange occurred too fast to be observed with the available time resolution. Fitting the particle diameter and membrane thickness of the hollow sphere model to the data, gave results which were in good agreement with Dynamic Light Scattering (DLS) data and literature, showing as a proof-of-principle that SESANS is able to investigate such systems.

SESANS may become a good alternative to conventional tritium studies or a tool with which to study intracellular vesicle transport phenomena, with possible in vivo applications. Calculations show that a substantial change in numbers of a mixed system of small and large biological particles should be observable. A possible application is the destruction by external means of great numbers of liposomes in the presence of tumor cells for triggered drug release in cancer treatment. Since SESANS is both non-invasive and non-destructive and can handle relatively thick samples, it could be a useful addition to more conventional techniques.

The structure of self-assembly domain containing recombinant truncation mutants of Lactobacillus brevis surface layer protein SlpA in aqueous solution was studied using small-angle X-ray scattering and transmission electron microscopy. The proteins were found out to interact with each other forming stable globular oligomers of about 10 monomers. The maximum diameter of the oligomers varied between 75 Å and 435 Å.

The effect of osmotic pressure on the structure of large uni-lamellar vesicle (LUV) of the lipid mixtures of monosialoganglioside (G_M1)-cholesterol-dioleoyl-phosphatidylcholine (DOPC) was studies by using wide-angle X-ray scattering (WAXS) method. The molar ratios of the mixtures were 0.1/0.1/1, 0/0.1/1, and 0/0/1. The ternary lipid mixture is a model of lipid rafts. The value of osmotic pressure was varied from 0 to 4.16×10⁵ N/m² by adding the polyvinylpyrrolidone (PVP) in the range from 0 to 25 % w/v. In the case of the mixtures without G_M1, the rise of the osmotic pressure just enhances the multi-lamellar stacking with deceasing the inter-lamellar spacing. On the other hand, the mixture containing G_M1 shows the structural transition from a uni-lamellar vesicle to a double-layered vesicle (a liposome including a smaller one inside) by the rise of osmotic pressure. In this morphology transition the total surface area of the double-layered vesicle is mostly as same as that of the LUV at the initial state. The polar head region of G_M1 is bulky and highly hydrophilic due to the oligosaccharide chain containing a sialic acid residue. Then, the present results suggest that the existence of G_M1 in the outer-leaflet of the LUV is essentially important for such a double-layered vesicle formation. Alternatively, a phenomenon similar to an endo- and/or exocytosis in cells can be caused simply by a variation of osmotic pressure.

The anionic phospholipid DMPG (dimyristoyl phosphatidylglycerol) may exhibit in water, instead of a unique melting transition of the hydrocarbon chains, a "melting regime" for pH values above 5, where the phosphate groups are deprotonated, and for low ionic strength, where charge screening is weak. The chain-melting process of DMPG starts at (onset of the melting regime at ∼ 20°C), but the complete fluid phase exists only above (offset of the melting regime at ∼ 30°C). In a recent paper we developed a SAXS model for a bilayer with pores to explain SAXS results obtained for concentrations up to 70 mM DMPG (F. Spinozzi, L. Paccamiccio, P. Mariani, and L. Q. Amaral, Langmuir, in print, 2010). A new lamellar phase with pores, starting 3°C above and existing up to 4°C above , was also identified at the higher investigated DMPG concentrations (up to 300 mM DMPG). In this paper we focus in more detail the SAXS curves obtained in the concentration interval 70-300 mM DMPG. The slope of the scattering profile in the very small q range, as well as the anomalous increase in the intensity of the bilayer band centered around 0.12 Å⁻¹ after , have been in particular analyzed. By using a model of water-penetrated bilayers, the volume fractions of DMPG and water molecules inside the bilayer was derived as a function of temperature.

The state of proteasome activator 28 (PA28) and the formation of the proteasomal complex in an aqueous solution are investigated with small-angle neutron scattering (SANS). The most appropriate state of PA28, which well reproduces the observed SANS profile, is the dissociation equilibrium between dimer and monomer with dissociation degree of 0.5. In addition, it is revealed that the packing of PA28 in the dimer is same as that in a crystal. It is also revealed that the proteasomal complex in which two PA28s connects to both basal planes of the 20S proteasome is spontaneously formed in the mixture solution of PA28 and the 20S proteasome.

Cardiolipin (CL) is a membrane phospholipid containing four fatty acid chains. CL plays an important role in energy transformation in mitochondria. The disorder of CL biosynthesis is involved in a genetic disease, Barth syndrome. Alteration of fatty acid composition of CLs has been found in Barth syndrome patients, i.e., the decrease of unsaturated fatty acid chains. In this study, we investigated how the degree of saturation alters the structure of CL bilayers by using X-ray scattering. Bovine heart CL and two synthetic CLs were compared. Fatty acid compositions of these three CLs have different saturation. Small-angle X-ray scattering data showed that the decrease of the number of double bonds in the unsaturated fatty acid chains causes to thicken the CL bilayers. In addition, wide-angle X-ray scattering data suggested that the decrease reduces the degree of disorder of the hydrophobic region in a liquid crystalline phase. These results may be related to the dysfunction of mitochondria in Barth syndrome.

Phase separated Ni-Nb-Y metallic glasses were prepared by means of rapid quenching from the melt. Quantitative Anomalous Small-Angle X-ray Scattering experiments were performed at the K-absorption edges of Nickel, Niobium and Yttrium. The paper outlines, that the separation of the pure-resonant scattering contribution is obtained by employing the Gaussian algorithm on a vector equation. Moreover the quantitative analysis of the Resonant Invariant at the K-absorption edges of Niobium and Yttrium provided the chemical concentrations of Yttrium and Niobium in the random density fluctuations, which are attributed to spinodal decomposition. The results are compared to a partially crystallized sample annealed at 773 K over 30 minutes.

Using a selective phase dissolution technique, nano-porous membrane can be produced from simple two-phase metallic alloys. It contains through-thickness elongated channel-like pores of only a few hundred nanometer width and has a number of prospective applications. Knowledge of microstructural parameters is essential for membrane optimization. Non-destructive characterisation of the pore microstructure was carried out by small-angle neutron scattering technique. The combined results from pinhole and double-crystal facilities enabled to determine microstructural parameters of the nanoporous membrane (pore-to-pore distance, raft thickness, pore volume fraction, specific interface). The contrast variation using D₂O and H₂O helped to conclude on scattering length density of both γ' pore walls as well as the original γ-phase matrix. The kinetics experiment showed that the pores are filled instantly by liquid. The subsequent emptying of pores by evaporation was observed.

The early caries lesion in bovine tooth enamel was studied by two different X-ray diffraction systems at the SPring-8 third generation synchrotron radiation facility. Both allowed us simultaneous measurement of the small and large angle regions. The beam size was 6μm at BL40XU and 50μm at BL45XU. The small-angle scattering from voids in the hydroxyapatite crystallites and the wide-angle diffraction from the hydroxyapatite crystals were observed simultaneously. At BL40XU an X-ray image intensifier was used for the small-angle and a CMOS flatpanel detector for the large-angle region. At BL45XU, a large-area CCD detector was used to cover both regions. A linear microbeam scan at BL40XU showed a detailed distribution of voids and crystals and made it possible to examine the structural details in the lesion. The two-dimensional scan at BL45XU showed distribution of voids and crystals in a wider region in the enamel. The simultaneous small- and wide-angle measurement with a microbeam is a powerful tool to elucidate the mechanisms of demineralization and remineralization in the early caries lesion.

Mixtures of β-sitosterol and γ-oryzanol form a network in triglyceride oil that may serve as an alternative to the network of small crystallites of triglycerides occurring in regular oil structuring. The present x-ray diffraction study investigates the relation between the crystal forms of the individual compounds and the mixture in oil, water and emulsion. β-Sitosterol and γ-oryzanol form normal crystals in oil, in water, or in emulsions. The crystals are sensitive to the presence of water. The mixture of β-sitosterol + γ-oryzanol forms crystals in water and emulsions that can be traced back to the crystals of the pure compounds. Only in oil, a completely different structure emerges in the mixture of β-sitosterol + γ-oryzanol, which bears no relation to the structures that are formed by both individual compounds, and which can be identified as a self-assembled tubule (diameter 7.2±0.1 nm, wall thickness 0.8±0.2 nm).

Coherent small angle X-ray scattering methods have been used to investigate the structure and dynamics of charged colloidal systems with different volume concentration. The static structure factor indicates that the degree of ordering depends on both the electrostatic interactions and the volume fraction. All systems showed a compressed exponential form of the dynamic structure factor. The Q-dependence of the relaxation time τ hints towards ballistic motion of the colloidal particles in the glassy state. For the sample with the highest volume fraction we observe an influence of the static structure factor on the relaxation rate of the particles indicating a caging effect also for the ballistic type of motion.

The size and size distribution of PMMA nanoparticles has been investigated with SAXS (small angle X-ray scattering) using monochromatized synchrotron radiation. The uncertainty has contributions from the wavelength or photon energy of the radiation, the scattering angle and the fit procedure for the obtained scattering curves. The wavelength can be traced back to the lattice constant of silicon, and the scattering angle is traceable via geometric measurements of the detector pixel size and the distance between the sample and the detector. SAXS measurements and data evaluations have been performed at different distances and photon energies for two PMMA nanoparticle suspensions with low polydispersity and nominal diameters of 108 nm and 192 nm, respectively, as well as for a mixture of both. The relative variation of the diameters obtained for different experimental conditions was below ± 0.3 %. The determined number-weighted mean diameters of (109.0 ± 0.7) nm and (188.0 ± 1.3) nm, respectively, are close to the nominal values.

A small-angle neutron scattering (SANS) which is a powerful technique to reveal the large scale structures was applied to investigate the fractal structures of water-based Fe₃O₄ferrofluid, magnetic fluid. The natural magnetite Fe₃O₄ from iron sand of several rivers in East Java Province of Indonesia was extracted and purified using magnetic separator. Four different ferrofluid concentrations, i.e. 0.5, 1.0, 2.0 and 3.0 Molar (M) were synthesized through a co-precipitation method and then dispersed in tetramethyl ammonium hydroxide (TMAH) as surfactant. The fractal aggregates in ferrofluid samples were observed from their SANS scattering distributions confirming the correlations to their concentrations. The mass fractal dimension changed from about 3 to 2 as ferrofluid concentration increased showing a deviation slope at intermediate scattering vector q range. The size of primary magnetic particle as a building block was determined by fitting the scattering profiles with a log-normal sphere model calculation. The mean average size of those magnetic particles is about 60 – 100 Å in diameter with a particle size distribution σ = 0.5.

Inverse photonic nickel-based crystal films formed by electrocrystallization of metal inside the voids of polymer artificial opal have been studied using the microradian X-ray diffraction. Analysis of the diffraction images agrees with an face-centred cubic (FCC) structure with the lattice constant a₀ = 650 ± 10 nm and indicates two types of stacking sequences coexisting in the crystal (twins of ABCABC... and ACBACB... ordering motifs), the ratio between them being 4:5 The transverse structural correlation length L_tran is 2.4 ± 0.1 μm, which corresponds to a sample thickness of 6 layers. The in-plane structural correlation length L_long is 3.4 ± 0.2 μm, and the structure mosaic is of order of 10°.

The effects of different solvents on the structure of microcrystalline and nanofibrillated cellulose (MCC, NFC) were studied using small-angle x-ray scattering (SAXS). MCC was immersed in water, ethanol, and acetone, and NFC was immersed only in water and ethanol, but studied also in the form of foam-like water-NFC-gel in wet, air-dried and re-wet states. The solvent affected the average chord length, which reveals the typical length scale of the structure of the sample: 2.4 ± 0.1 nm was obtained for MCC-water, 2.5 ± 0.1 nm for re-wet NFC-gel, 1.6 ± 0.1 nm for MCC-ethanol, 1.2 ± 0.1 nm for NFC-ethanol, and 1.3 ± 0.1 nm for MCC-acetone. The specific surface of cellulose increased strongly when MCC and NFC were immersed in the solvents compared to dry cellulose. The specific surface of cellulose was determined to be larger for NFC-water than MCC-water, and slightly larger for dry NFC powder than for dry MCC, which can be explained by the fact that the width of cellulose crystallites perpendicular to the cellulose chain direction was slightly larger in MCC than in NFC on the basis of wide-angle x-ray scattering results.

Callus tissue formed during bone fracture healing is a mixture of different tissue types as revealed by histological analysis. But the structural characteristics of mineral crystals within the healing callus are not well known. Since two-dimensional (2D) scanning small-angle X-ray scattering (sSAXS) patterns showed that the size and orientation of callus crystals vary both spatially and temporally [1] and 2D electron microscopic analysis implies an anisotropic property of the callus morphology, the mineral crystals within the callus are also expected to vary in size and orientation in 3D. Three-dimensional small-angle X-ray scattering (3D SAXS), which combines 2D SAXS patterns collected at different angles of sample tilting, has been previously applied to investigate bone minerals in horse radius [2] and oim/oim mouse femur/tibia [3]. We implement a similar 3D SAXS method but with a different way of data analysis to gather information on the mineral alignment in fracture callus. With the proposed accurate yet fast assessment of 3D SAXS information, it was shown that the plate shaped mineral particles in the healing callus were aligned in groups with their predominant orientations occurring as a fiber texture.

The use of grazing incidence small and intermediate angle X-ray scattering in the study of structure and alignment of thermotropic liquid crystals is illustrated on selected examples. These include columnar LC phases of a star-shaped mesogen, several honeycomb phases of T-shaped and X-shaped bolaamphiphilic LCs, and gold nanoparticles coated with mesogenic ligands. Sharp Bragg reflections from systems with 2-d and 3-d periodicities are obtained through annealing. Due to nearly perfect surface alignment in most cases, indexing of complex diffraction patterns is facilitated. Honeycomb cells with deformed hexagonal cross-sections, as well as kagome lattice, are shown. The tilt of the reciprocal lattice is shown to help establish the correct structure in the case of the stretched hexagonal honeycombs and the rhombohedral arrays of ordered strings of gold nanoparticles.

Structural and magnetic properties of two-dimensional spatially ordered system of ferromagnetic cobalt nanowires embedded into Al₂O₃ matrix have been studied using polarized small-angle neutron scattering. The small-angle scattering pattern exhibits many diffraction peaks (up to the third reflection order), which corresponds to the scattering from highly correlated hexagonal structure of pores and magnetic nanowires. A comprehensive analysis of contributions to the scattering intensity, including nonmagnetic (nuclear) contribution, magnetic contribution depending on the magnetic field, and nuclear-magnetic interference indicating the correlation between the magnetic and nuclear structures was carried out. A detailed pattern of the remagnetization of an ordered array of the magnetic nanowires has been obtained. It has been illustrated that polarized neutron scattering provides unique information inaccessible by the standard magnetometry techniques.

The friction-stir welding (FSW) process induces both heat and deformation which lead to inhomogeneous precipitation microstructures in structural hardening alloys. A map of this microstructure can be obtained by 2D scanning SAXS in alloys where (a) a single phase is precipitating and (b) the precipitates are roughly isotropic. In Al-Li-Cu alloys, these conditions are not fullfilled. Very anisotropic precipitates are forming (T1 and θ') with aspect ratios in the range 10 to 100. The inhomogeneity in the texture of the material (due to the deformation and recrystallisation) is a strong obstacle to the interpretation of the SAXS signal. This paper is an attempt to apply systematic simple interpretation models to characterise the precipitation microstructure across the weld area. It shows that in certain condition, it is possible to apply simple Guinier-type plot to extract the morphologies (length and thickness) of the particles.

The effect of neutron irradiation on the formation of defect/solute clusters in binary iron alloys is important for the understanding of the damage mechanisms in structural materials applied in the field of nuclear technology. The irradiation behaviour of four binary Fe-Cr alloys of commercial purity with chromium contents between 2.5 and 12.5at% and neutron exposure of 0.6 and 1.5 dpa at 300 °C has been studied by SANS. The analysis of the experimental results indicates that there are at least two populations of irradiation-induced features. The appearance of α-phase particles was shown for Fe-12.5at%Cr and to a less content in Fe-9at%Cr. We have observed a strong and complex effect of Cr and weak or insignificant effects of neutron exposure.

X-ray powder diffraction (XRD) and small-angle neutron scattering (SANS) experiments were carried out for the hydrogenated and duterated Mg₂Ni, respectively. According to the results of XRD experiments, both of them coexisted with unhydrogenated (or undeuterated) Mg₂Ni in the hydrogen absorbing cycle. Furthermore, in the SANS experiments, a slope of SANS curve, I(Q), was roughly evaluated by using the following power law: I(Q) ∝ Q^−m, where Q is the magnitude of the scattering vector, and m can be equated with a fractal dimensionality, D_S (= 6 − m). In conclusion, the hydrogenated and duterated Mg₂Ni showed D_S∼ 3 and ∼ 2, respectively. The significant difference between D_S's can be understood by considering the scattering length densities, ρ, of Mg₂Ni, Mg₂NiH₄, and Mg₂NiD₄.

Microstructure evolutions of nano-quasicrystals precipitated in ZrCuPt metallic glass ribbons during annealing has been examined by in-situ small-angle scattering and wide angle diffraction (SWAXS). The time-resolved measurements were made at a photon energy close to the Zr K absorption edge to obtain reasonable balance between transmission and resolution. During annealing the sample in vacuum, increase in SAXS intensity and diffraction peak at medium angle region was observed. The size obtained from SAXS and diffraction almost agreed, suggesting that the precipitation process in the glass ribbon is described by a growth process of single-crystalline nano-quasicrystals. Development of precipitated microstructure was further discussed by comparing SAXS profiles and diffraction profiles.

The early stages of precipitate formation in Fe-25at% Co-9at% Mo at 500 °C was investigated by in situ small-angle neutron scattering (SANS). The ratio of magnetic to nuclear SANS intensity, which depends on the precipitate composition, and the precipitate sizes were analyzed. The results suggest that in the Fe-Co-Mo alloy an initial stage of precipitate formation with strong compositional changes is completed after 150 s, when the full magnetic signal is established. For comparison, the well-known nucleation and growth reaction in Fe-1at% Cu was studied. Differences in the growth rate of the mean size of the developing structures could be distinguished in the two investigated alloys. While in the Fe-Co-Mo alloy the precipitate structures grow with t^0.15 to t^0.21, the mean precipitate radius in the Fe-Cu alloy grows with t^0.40 in the observed time interval.

Main changes which appear in microstructure of Ni base superalloys during creep exposure is the directional coarsening (rafting) of originally cubic γ' precipitates embedded in γ matrix. The progress in γ' degradation can be assessed with help of the analysis of geometrical parameters of the γ' microstructure. Determination of the morphological changes of γ' in creep-exposed single-crystal Ni-base superalloy CMSX4 using SANS was carried out. A new sample design (conic specimen) was tested in order to get continually changing stress levels in one sample and corresponding variety of micro structural change. Evolution of rafts with stress magnitude is clearly observable from the parameters obtained using SANS (the mean thickness of the γ channel in different crystallographic directions of the single-crystal, the evolution of the γ' precipitate size and distance, the evolution of the specific interface). The use of conic specimen and spatial scan facilitate determination of microstructure evolution in dependence on the exposure parameters.

Lyotropic order-disorder transition (ODT) in a semi-dilute solution of an ultra-high-molecular-weight block copolymer using a neutral solvent and a differentiating non-solvent was investigated. The role of the differentiating non-solvent in the ODT was revealed by the spatial distribution of the solvents simulated theoretically by the self-consistent field (SCF) theory approach and demonstrated experimentally by small-angle neutron scattering (SANS). The solutions of polystyrene-block-poly (tert-butyl methacrylate) (PS-b-PtBuMA) with an ultra-high-molecular-weight (UHMW) in a mixture of tetrahydrofuran (THF)/ water as a good and neutral solvent and a differentiating non-solvent, respectively, were used. The contrast variation method by SANS experimentally demonstrated that THF and water collectively move into the PtBuMA phase and that the volume fraction ratios of water to THF in both phases are almost equivalent to each other. This means that the solvent mixture of THF and water behaves as a single and strongly selective solvent. The collective movement of the solvents was well reproduced by the simulation. Interestingly, it was also suggested that THF gather in the vicinity of styrene-(tert-butyl methacrylate) interface to shield the unfavorable strong interaction between the PS and the PtBuMA phases and that water gather in the center of the PtBuMA phase to decrease the unfavorable contact with the PS phase.

The structural modifications induced by changes in temperature are investigated by Small-Angle X-ray Scattering (SAXS) over a broad range of q-values (3.5×10^-2 – 12 nm^-1) in cryogels based on N-isopropylacrylamide (NIPA) and/or 2-Hydroxyethyl methacrylate-L-Lactide-Dextran (HEMA-LLA-D) macromer. Various copolymeric cryogels of these two monomers are prepared by cryopolymerization yielding macroporous gels (cryogels). For the plain pNIPA cryogel, the SAXS curves obtained at each temperature are well fitted by a sum of four equations describing respectively the scattering resulting from the gel surface (power law), from the solid-like (Guinier equation) and liquid-like (Ornstein-Zernike equation) heterogeneities and from the chain-chain correlation yielding a broad peak (pseudo-Voigt equation) in the high-q domain. The temperature dependence of the parameters obtained from the fit is analyzed and discussed. It is shown that the existence of an isoscattering (or isosbestic) point observed in pNIPA gels and in some copolymers is related to features observed by Differential Scanning Calorimetry and swelling ratio measurements.

Electrospinning is a technique employed to produce nanoscale to microscale sized fibres by the application of a high voltage to a spinneret containing a polymer solution. Here we examine how small angle neutron scattering data can be modelled to analyse the polymer chain conformation. We prepared 1:1 blends of deuterated and hydrogenated atactic-polystyrene fibres from solutions in N, N-Dimethylformamide and Methyl Ethyl Ketone. The fibres themselves often contain pores or voiding within the internal structure on the length scales that can interfere with scattering experiments. A model to fit the scattering data in order to obtain values for the radius of gyration of the polymer molecules within the fibres has been developed, that includes in the scattering from the voids. Using this model we find that the radius of gyration is 20% larger than in the bulk state and the chains are slightly extended parallel to the fibre axis.

We report the relationship between macroscopic properties (swelling ratio, breaking stress and strain) and the network microstructure of PVA cast gel. Swelling in water solvent and drying in air were alternately repeated, where water was exchanged by new water before each swelling. The effects of the number of water exchange, N on the macro- and microscopic properties were examined in detail. As a result, the swelling ratio of PVA cast gel decreased, and both of breaking stress and strain increased with increasing N. The measurements using X-ray diffraction (XRD) indicated that the average distance between the microcrystallites decreased due to the formation of the additional microcrystallites during the repeated processes of water exchange with drying. On the other hand, the measurements using Fourier Transform Infrared (FT-IR) Spectroscopy suggested that the microcrystallites and hydrogen bonds between polymers increased during the repeated processes.

In-situ observation was conducted on an operating polymer electrolyte fuel cell with a combined method of small-angle neutron scattering (SANS) and neutron radiography (NR). The combined measurement system has been recently developed to visualize water in a wide length scale from nano- to millimeter and successfully detected a spatial distribution of the water generated in individual cell elements; NR macroscopically detected the water in a gas diffusion layer and a flow-field, whereas SANS microscopically did in a membrane electrode assembly. In particular SANS was found to be a strong tool to make a rather precise analysis on the water content inside of ion conducting channels of polymer electrolyte membrane.

The effect of counter-ion species on the local conformation of fully-charged poly(L-glutamate) in added-salt aqueous solutions were studied by small-angle X-ray scattering(SAXS). In the case of presence of monovalent counter-ion, the scattering behaviour could be explained by taking into consideration the excluded volume effect and intermolecular-interface interaction on the scattering function of wormlike chain. On the other hand, since SAXS profile of the solution in the presence of divalent counter-ion well fitted to the scattering function of dendrimer, it suggested that the conformation of polymer chain in such solution would be more compact conformation than that of presence of monovalent ion.

We report on the stability and cluster formation in C₆₀ fullerene-polystyrene mixtures, using a combination of small angle neutron scattering, optical and atomic force microscopy. Bulk nanocomposites are found to be stable for C₆₀ loadings up to 1-2% mass fraction in PS of M_w = 270 kg/mol and approximately 160°C. At larger fullerene concentration, the coherent scattering intensity grows with time, within 10s of min, and is well described by an asymptotic relationship with rate compatible with Arrhenius temperature dependence. The nanocomposite structure can be described by fractal scattering with a broad range of dimensions D_f ∼1.85-2.4 and polydisperse fractal sizes, up to hundreds of nm, depending on annealing temperature and time. Confinement in thin films of tens to hundreds of nm is shown to result in well-defined surface topographies, ranging from isolated clusters to percolated spinodal-like undulations with tuneable wavelength and amplitude. These results provide insight into the control of dispersion and self-assembly of nanoparticles in polymer matrices and thus their exploitation in functional materials, including organic photovoltaics and thin film coatings.

Recently developed equipment suitable for quasi simultaneous data collection of SAXS/WAXS and X-ray spectroscopy is discussed. The main applications for this technique are foreseen to be time-resolved studies in inorganic materials relevant for catalysis research and ceramics. The equipment is described and experimental limitations are discussed. Experiments on nanoparticle synthesis and the formation of inorganic materials for catalysis are used as examples of the usefulness of the developed equipment.

An X-ray photon correlation spectroscopy (XPCS) study of composite-type material consisting of polyurethane gel and carbonyl iron micrometric spheres was performed under magnetic fields of 0, 300 and 600 mT. The onion-like spheres structure was destroyed during the composite processing. The following conclusions were obtained from the study: -The polyurethane matrix is preferred as a source for the observed dynamic effects. -Below 300mT the material dynamics in direction of the outer magnetic field are very clear. -For 600 mT the dependence of the dynamics on magnetic field direction disappears, but the correlation rate is much higher. These findings may be caused by a disturbance of the polymer mesostructure by larger strain leading to its cross-linking.

The aim of these studies is to establish sound scientific principles to guide nucleation rate and the selection of a desired polymorph via the application of mechanical energy – ultrasound (US) irradiation. When delivered to a metastable liquid, before the offset of nucleation and under constant temperature and supercooling conditions, the wave nature of this simple form of energy should be critical for defining different crystallisation pathways of polymorphic materials including polymorph selection. To test this hypothesis, we crystallized a melt-grown trilaurin (LLL), a typical polymorphic triacylglycerols (TGA's), with and without US by using in-situ simultaneous synchrotron radiation time-resolved small-angle X-ray scattering (SAXS) and wide angle X-ray scattering (WAXS), SAXS/WAXS. Without US application, both polymorphic forms β^' and β crystallized. With US treatment of the super cooled melt, the following effects were observed: (a) a marked decrease of induction times (b) an increased nucleation rate, and (c) selective crystallization of only β-form when crystallised at 25 and 30°C with input powers of 20 and 100 W and a sonication time of 2 s. Combining the existing knowledge on the dynamic nucleation of collapsing cavities and a qualitatively developed (P-T) phase diagram for the TGA's, it was possible to describe, for the first time, the behaviour of the most important parameters and the events that characterize the crystallization of these systems. It was shown that the interplay of sonication and the temperature of supercooled melts are critical to the selection of a stable β form.

We report a combined microfluidic and online synchrotron small-angle X-ray scattering (SAXS) study of complex surfactant mixtures under flow. We investigate the influence of a series of flow constrictions, generating well-defined, periodic extensional flow fields, on the microstructure of two model surfactant mixtures containing SDS and CTAC. Specifically, the lamella spacing, orientation and structural order are reported and correlated with the imposed flow field: geometry, flow velocity and residence time. The design, fabrication and operation of a microfluidic system using rapid prototyping is described in detail. We show that polydimethyl siloxane (PDMS), ubiquitous in microfabrication, provides a suitable matrix for SAXS microdevices provided that: (i) PDMS thickness are kept to a minimum while retaining structural integrity (∼1000μm) and (ii) scattering from the structure of interest is sufficiently decoupled from the amorphous background scattering. The combination SAXS-microfluidics provides unprecedented opportunities to elucidate the non-equilibrium structure formation and relaxation of complex fluids, demonstrated here for concentrated surfactant mixtures.

Although metallic nanoparticles play an important role in the area of nanotechnology, a coherent mechanistic explanation for the evolution of the particles during their chemical synthesis has not yet been provided in many cases. To gain a profound understanding of the growth mechanism of colloidal nanoparticles, new approaches using Small Angle X-Ray Scattering (SAXS) combined with X-ray absorption near-edge structure (XANES) are presented. This combination allows for insights into two prominent syntheses routes of gold nanoparticles (GNP): The "slow" reaction using sodium citrate (30-90 min) as a reducing agent and the "fast" reaction employing NaBH₄ (within few seconds). In the first case data derived with the coupled XANES and SAXS suggests a four-step particle formation mechanism. For the second system a time resolution in the order of 100-200 ms was achieved by coupling a common laboratory SAXS instrument with a microstructured mixer, which allows data acquisition in a continuous-flow mode. The results indicate a coalescence driven growth process. Based on the capabilities to deduce the size, number and polydispersity of the particles, the results of both methods enable the development of mechanistic schemes explaining the different phases of particle formation and growth, thus providing a basis for improved control over the synthesis processes.

We discuss the application of in-situ rheological small angle X-ray scattering experiments to the study of complex fluids under shear, implemented using custom Couette cylinder rheometers mounted on the SWING beamline of the SOLEIL Synchrotron. We discuss several applications of this technique to the study of phase transitions in nanoparticle doped liquid crystals and shear alignment of clay suspensions. The concurrent capture of rheological and scattering data provides vital information that relates macroscopic properties such as viscosity to the microstructure of the fluid.