SAXS method

Stmctural and chemical modification of urethane containing polymer matri-ces with macrocycles - calixarenes having reactive hydrazide groups have been carried out and stmcture, physico chemical and sensor properties of polyure-thanesemicarbazides (PUS) synthesised have been studied. The polymers obtained (on the base of polypropylene glycol MM 1000 and polysiloxane diol MM 860, hexamethylene diisocyanate and calixarene dihydrazide) are identified by IR-spectroscopy, size exclusion chromatography (SEC), DSC, WAXS and SAXS methods. 

Power and Limits of the SAXS Methods. This field of SAXS is in competition with the field of protein crystallography. The spatial resolution of the SAXS method is limited (> 0.5 nm), whereas structures determined by protein crystallography are exact up to fractions of Angstrpms. On the other hand, the protein crystallography is unable to study living proteins under almost physiological conditions. Moreover, kinetic processes can be monitored by SAXS but cannot be studied by means of protein crystallography. 

Perfection of Structure in Nanostructured Materials. An aim of modern nanotechnology is the fabrication of materials with highly perfect structure on the nanometer scale. The distortion of such nanostructured materials can be studied by SAXS methods. Frequently the material is supplied as a very thin film with predominantly uniaxial correlation among the nanodomains. Under these constraints the nanodomains are frequently arranged in such a way that the normal to the film is a symmetry axis rotation of the film on the sample table does not change the scattering (fiber symmetry). 

PbS-PPX nanocomposite with 4.7 vol.% of PbS was investigated also by small angle X-ray scattering (SAXS) method, which characterizes different... 

For such mechanism the size of the ring of cyclic polymer formed would be closely related to the thickness of lamellar crystals. The thickness of crystals has been measured by SAXS method and good linear dependence between the molecular weight of cyclic polymer (M -1300-2100) and the long period of the crystal (—7-9 nm) was observed. The quantitative relation between M of cyclic fraction and parameters of crystalline phase can be expressed as follows ... 

Among all the techniques listed in this heading X-ray Scattering , the SAXS method is probably one of the most often used. The studies of phase separation and recrystallization in organic polymers or polymer mixtures very often requires SAXS experiments. In the inorganic chemistry field too, this method is used to tackle a variety of scientific purposes ... 

Pons et al. have also followed the dessication-rehydration cycle in the montmoril-lonite clays by the SAXS method. This is an interesting study because the swelling properties of clays play an important role in the structural organization of soils. Two main conclusions arise from this work ... 

Great majority of polymer blends have the domain size in the range of 50 nm to 5 pim. For this reason the LS and SAXS methods have limited use for studies of their morphology, while SANS is preferred. The latter method has been used to study macromolecular sizes, conformation and morphology, in a single or multicomponent system, in molten or solid state. Since the dis-... 

PS/PMMA P(S-b-MMA) Increasing thickness of the P(S-b-MMA) layer between PS and PMMA to 23.9 nm caused a gradual increase of A1 from 5 to 8.4 nm. Micellar segregation at the interface of samples was not observed by the elastic recoil detection method. SAXS method was used. Upon addition of the copolymer the interface thickness changed from A1 = 2 to 6 nm Russel e/a/., 1991 Jeon and Roe, 1994 Perrin and Prud homme, 1994... 

PP/HIPS SB WAXS and SAXS methods. Addition of a SB slightly reduced crystallinity of a-PP. Hlavata and Horak, 1994... 

A PbS-PPX nanocomposite with 4.7 vol. % of PbS was investigated also by the small-angle X-ray scattering (SAXS) method, which characterizes different PbS inclusions in PPX matrix regardless of their internal structure. The size distribution of PbS inclusions calculated from SAXS data is similar to the WAXS crystallite size distribution on Figure 2.10. This result signifies that PbS nanoparticles do not aggregate in matrix but are distributed in PPX mostly as small crystallites [53]. 

Figure 5.10 illustrates a high-resolution image of single BaTi03 nanoparticle prepared in microemulsions and measured by the SAXS method. The powder particles have a size smaller than 10 nm. 

SAXS method was used. Upon Perrin and Prud homme... 

Synthesis of a new modification of silica soluble in THF is described. At the first synthetic step, a hyperbranched polyethoxysiloxane (HBPES) is synthesized by heterofunctional condensation using triethoxysilanol previously generated in reaction mixture by neutralization of correspondent sodium salt with acetic acid. At this step, the process was monitored by IR spectroscopy, SEC, and Si NMR spectroscopy. At the second step, hydrolysis and intramolecular condensation involving silanol groups is carried out to yield silica sol macromolecules. A SAXS method was used to determine the size and fractal coefficient of trimethylsilated derivatives and silica sols obtained. An atomic-force microscopy imaging of silica sol supported on a mica substrate showed the silica sol particles to be predominantly spherical in shape. Prospects for theoretical, experimental and practical applications of silica sols are discussed. 

Titov et al. studied the detonation process using synchrotron radiation and the Small Angle X-ray Scattering (SAXS) method with exposure time of one nanosecond and 125 nanoseconds between exposures. While the SAXS procedure can not separate the signals from nano-diamond and non-diamond carbon forms, the Russians are trying to use it to resolve when and how much carbon is formed in a detonation wave. 

Literature at a glance. Static investigations of strained polymer materials are, in fact, the earliest demonstrations of the SAXS method [7-9]. Tb this day, fibers and other nanocomposite materials are subjected to mechanical tests and investigated by X-ray scattering. Results of such experiments have fostered important developments in the field of SAXS theory. As an example, the fundamental work of Porod [10,11], Bonart [12-14] and Vonk [15] shall be mentioned. 

---