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The kinetics of secondary crystallization during spherulite growth of isotactic poly(propylene) (iPP) and poly(vinylidene flouride) (PVF 2 ) is studied using a novel technique that employs a micron size X-ray beam. The data are combined with separate conventional simultaneous on-line SAXS/WAXS measurements and optical microscopy studies. In our experiments, crystallization takes place at low undercooling so that slowly growing large single spherulites are obtained. The data reveal that the main mechanism of secondary crystallization is the growth of new lamellae stacks within remaining amorphous regions. It is shown that a substantial amount of crystallites form as a result of secondary crystallization while the spherulite is growing. Furthermore, secondary crystallization is strongest directly behind the boundary of the spherulite and is independent of its size or growth state. A separate, off-line microfocus study on a quenched spherulite sample confirms this observation; the crystallinity is higher in the main body of the spherulite and lower near the boundary, where crystallization progressed to a lesser degree.

The morphology of dewetted thin polymer-blend films of deuterated polystyrene (dPS) and polyparamethylstyrene (PpMS) on top of silicon surfaces is investigated. The film thickness of the originally homogeneous films is varied between 19 and 104 A. Compared to the radius of gyration of the unperturbed molecule, R g =106 A , the as-prepared films are confined in the direction perpendicular to the sample surface. The dewetting results from the storage of the samples under toluene vapor atmosphere. Atomic force microscopy (AFM) and grazing incidence small-angle scattering (GISAS) are used. From the differences in the GISAS data measured with X-rays compared to data measured with neutrons a random distribution of the molecules inside the individual droplets is determined. Thus from dewetting under toluene atmosphere no periodicity in the internal structure exists. The, within all methods derived, most prominent in-plane length corresponds to the mean droplet distance. Its function of film thickness is explainable by the spinodal dewetting model.

The glass with composition 13Na2O-11CaO-76SiO2 (mol%) undergoes subliquidus phase separation via a binodal mechanism. At temperatures below the binodal temperature, T b = 978 K, the glass separates into two amorphous phases, silica-enriched droplets and a silica-poor matrix. Small-angle X-ray scattering was used to study the formation of the droplet phase at 923 K as well as the process of reversion where the precipitates dissolve after an increase in temperature. After a heat treatment of 48 h at 923 K the system is in the stage of coarsening. However, the equilibrium volume fraction of the droplet phase, w e = 0.073, has not yet precipitated. The reversion of the droplets was studied at T = 983 K and T = 963 K. For T > T b, the precipitates dissolve completely by an interdiffusion process resulting in a decrease of the silica concentration of the droplets, while the phase boundary is preserved over long times. For T < T b, the reversion process shows two distinct stages. In the first stage, the silica concentration inside the droplets decreases and all precipitates shrink until the concentration in the matrix reaches its new equilibrium value. Afterwards, the largest droplets grow again by slow coarsening.

We show that the accessible range of length scales of structures deduced with ultra small-angle scattering (USAX) experiments can be enlarged by more than one order of magnitude in reflection geometry set-ups. From the analysis of the diffuse scattering without further model assumptions the length scale of the structures is determinable. The method is illustrated by an example of thin blend films of deuterated polystyrene (dPS) and polyparamethylstyrene (PpMS) where μm-structures are recovered. The results are compared to atomic-force microscopy measurements. For a further comparison, USAX data of a water-based dispersion of polymer particles are presented. They illustrate the resolvable length scale of the conventional transmission geometry.

The lateral structures of dried adsorbed binary mixtures of star polymers were investigated. Blends of protonated and deuterated polybutadiene stars were prepared from cyclohexane solutions and adsorbed onto silicon substrates. The number of arms and the molecular weight of the arms was varied. With grazing incidence small angle scattering techniques (GISAS) and scanning force microscopy (SFM), different dominant in-plane length scales were determined. The morphology of these structures is dominated by blob-like structures created from single stars or agglomerates of star polymers.