In this work we evaluate the potential of grazing incidence X-ray scattering techniques in the investigation of laserinduced periodic surface structures (LIPSSs) in a series of strongly absorbing model spin-coated polymer films which are amorphous, such as poly(ethylene terephthalate), poly(trimethylene terephthalate), and poly(carbonate bisphenol A), and in a weaker absorbing polymer, such as semicrystalline poly(vinylidene fluoride), over a narrow range of fluences. Irradiation was performed with pulses of 6 ns at 266 nm, and LIPSSs with period lengths similar to the laser wavelength and parallel to the laser polarization direction are formed by devitrification of the film surface at temperatures above the characteristic glass transition temperature of the polymers. No crystallization of the surface is induced by laser irradiation, and crystallinity of the material prevents LIPSS formation. The structural information obtained by both atomic force microscopy and grazing incidence small-angle X-ray scattering (GISAXS) correlates satisfactorily. Comparison of experimental and simulated GISAXS patterns suggests that LIPSSs can be well described considering a quasi-onedimensional paracrystalline lattice and that irradiation parameters have an influence on the order of such a lattice.
This work demonstrates the use of wetting nanoporous alumina template with polymer solution to produce arrays of isolated poly(vinylidene fluoride) (PVDF) ferroelectric gamma-type nanorods supported within a nonpolar alpha-structure film. The method is based upon a crystal phase transition which occurs due to PVDF confinement within alumina nanoporous. The system was studied using scanning X-ray microdiffraction (micro-XRD) that allows the solid-solid phase transition from the alpha-nonpolar crystal form (bulk) to the gamma polar ferroelectric form (nanorod array) to be spatially resolved, as well as providing crystallinity and orientation information. The results reveal that the interaction between polymer chains and the porous membrane's walls imposes a flat-on lamella growth along the nanorrods long axis, while improving crystal orientation.
To achieve low percolation thresholds in single wall carbon nanotube (SWCNT) and
thermoplastic poly(butylene terephthalate) (PBT) composites, we have used an in situ polycondensation
reaction process. The intense dispersion process achieved first by ultrasonication and followed by ultrahigh
speed stirring of single wall nanotubes in 1,4-butanediol and the subsequent in situ polycondensation
has made possible the preparation of nanocomposites in which the percolation threshold is around 0.2
wt % of SWCNT. This relatively low value approaches those reported for carbon nanotube nanocomposites
based on thermoset polymers. On the basis of the structural measurements, we interpret that
agglomeration effects may enhance the formation of the conducting network.
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