Time-resolved SAXS profiles from

Figure Bl.9.13. Time-resolved SAXS profiles during isothermal crystallization (230 °C) of PET (the first 48 scans were collected with 5 seconds scan time, the last 52 scans were collected with 30 seconds scan time) calculated correlation functions y(r) (normalized by the invariant Q) and lamellar morphological variables extracted from the correlation functions (invariant Q, long period crystal lamellar thickness and...

The capability of combined nanoscale spatial and millisecond time resolution provided by SAXS is clearly revealed by a study involving the absorption of bovine serum albumin (BSA) onto spherical polyelectrolyte brushes (SPB). The experiment also highlighted the requirement of an advanced modeling capability for the complete exploration of the time-resolved SAXS data. The quantity of absorbed protein per brush as a function of time was provided from the radial electron density profile of SPB, which has been previously derived from the time-resolved SAXS intensities. Furthermore, an unexpected subdiffusive motion of proteins in the tethered polyelectrolyte brushes has been revealed. A quantitative explanation of this sub-diffusive mode can be approached in terms of a simple model involving direct motions of proteins enclosed in the effective interaction potential of the polyelectrolyte chains. 

The nature of the NIF form, at least in alkanes, has only been understood after electron density profiles normal to the lamellae had been reconstructed using SAXS intensities of a number of diffraction orders.59 It turns out that NIF is up to one-third amorphous, with some chains integrally folded in two and others not folded at all but traversing the crystalline layer only once (see Figure 6b). These latter chains are only half-crystalline, with their protruding ends, or cilia, forming the amorphous layer. From the crystalline layer thickness /<, determined from the electron density profile, and from 7lam = U2, determined from time-resolved Raman spectroscopy,61 it was established that the chains are tilted at 35° to the normal in the crystalline layers. 

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