Xia, "Effect of thermal annealing on ferroelectric domain structures in poly(vinylidene-fluoride-trifluorethylene) Langmuir-Blodgett thin films" (2014 We report a piezo-response force microscopy study of the effect of thermal annealing on ferroelectric domain structures in 6 to 20 monolayer (11 to 36 nm) polycrystalline poly(vinylidene-fluoridetrifluorethylene) thin films prepared using the Langmuir-Blodgett approach. Stripe-shape domains have been created at room temperature and subjected to thermal annealing at progressively higher temperatures up to the ferroelectric Curie temperature T C of approximately 110 C. The static configuration of the domain walls exhibits no appreciable temperature dependence after thermal annealing, with the domain-wall roughness exponent f ranging from 0.4 to 0.5. Above 80 C, we observed spontaneous polarization reversal at randomly scattered local sites in both polarization states. The number of domain nucleation centers increases rapidly as a function of temperature. We compared the thermally driven domain formation in ferroelectric polymers with those observed in ferroelectric oxides and attributed the difference to the distinct mechanisms for domain formation in these two systems. V C 2014 AIP Publishing LLC. [http://dx

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Surface pollution by Mg and carbon has been identified by X-Ray Photoelectron Spectroscopy (XPS) analysis on monophasic (100% stoichiometric hydroxyapatite) or biphasic (70% hydroxyapatite, 30% b-tricalcium phosphate) ceramics obtained by sintering of Ca-P powder of standard purity. Magnesium was the main impurity, although it is present only as traces in synthesised Ca-P powders, it concentrates on the surface of the ceramic during the sintering process due to its poor solubility in HA. Carbon pollution is common on all materials and generally assigned to the adsorption of atmospheric volatile organic compounds, although other types of pollution may occur. These surface species alter the surface energy of the ceramics which has been shown to be related to cell adhesion. The change in surface composition and physical properties can interfere with the sintering process as well as with the biological behaviour of the ceramics and a special effort should be made to control these events at all levels from processing to handling, storage and packaging.

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