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Focusing on the phase-coexistence region in Langmuir films of poly(L-lactide), we investigated changes in nonequilibrated morphologies and the corresponding features of the isotherms induced by different experimental pathways of lateral compression and expansion. In this coexistence region, the surface pressure II was larger than the expected equilibrium value and was found to increase upon compression, i.e., exhibited a nonhorizontal plateau. As shown earlier by using microscopic techniques [Langmuir 2019, 35, 6129-6136], in this plateau region, well-ordered mesoscopic clusters coexisted with a surrounding matrix phase. We succeeded in reducing Pi either by slowing down the rate of compression or through increasing the waiting time after stopping the movement of the barriers, which allowed for relaxations in the coexistence region. Intriguingly, the most significant pressure reduction was observed when recompressing a film that had already been compressed and expanded, if the recompression was started from an area value smaller than the one anticipated for the onset of the coexistence region. This observation suggests a "self-seeding" behavior, i.e., pre-existing nuclei allowed to circumvent the nucleation step. The decrease in Pi was accompanied by a transformation of the initially formed metastable mesoscopic clusters into a thermodynamically favored filamentary morphology. Our results demonstrate that it is practically impossible to obtain fully equilibrated coexisting phases in a Langmuir polymer film, neither under conditions of extremely slow continuous compression nor for long waiting times at a constant area in the coexistence region which allow for reorganization.
European coronationalism?
(2020)
The COVID-19 crisis has shown that European countries remain poorly prepared for dealing and coping with health crises and for responding in a coordinated way to a severe influenza pandemic. Within the European Union, the response to the COVID-19 pandemic has a striking diversity in its approach. By focusing on Belgium, France, Germany, and Italy—countries that represent different models of administrative systems in Europe—the analysis shows that major similarities and convergences have become apparent from a cross-country perspective. Moreover, coping with the crisis has been first and foremost an issue of the national states, whereas the European voice has been weak. Hence, the countries’ immediate responses appear to be corona-nationalistic, which we label “coronationalism.” This essay shows the extent to which the four countries adopted different crisis management strategies and which factors explain this variance, with a special focus on their institutional settings and administrative systems.