Ortho-Fluorination of azophenols increases the mesophase stability of photoresponsive hydrogen-bonded liquid crystals

Photoresponsive liquid crystals (LCs) whose alignment can be controlled with UV-Visible light are appealing for a range of photonic applications. From the perspective of exploring the interplay between the light response and the self-assembly of the molecular components, supramolecular liquid crystals are of particular interest. They allow elaborating the structure-property relationships that govern the optical performance of LC materials by subtle variation of the chemical structures of the building blocks. Herein we present a supramolecular system comprising azophenols and stilbazoles as hydrogen-bond donors and acceptors, respectively, and show that ortho-fluorination of the azophenol dramatically increases the thermal stability of the LC phases, an important characteristics in their further utilization in photonics. The systems exhibit fast photoinduced order-disorder transitions, and rapid recovery of the liquid-crystalline state once the light irradiation is ceased, due to the photochemical properties of azophenols.acceptedVersionPeer reviewe

Local actors in global politics

Globalization and the new information and communication technologies(ICTs) have enabled a variety of local political actors to enter inter-national arenas once exclusive to national states. Multiple types of claim-making and oppositional politics articulate these developments. Going global has been partly facilitated and conditioned by the infrastructure of the global economy, even as the latter is often the object of those oppositional politics. Further, and in my analysis, very importantly, the possibility of global imag-inaries has enabled even those who are geographically immobile to become part of global politics. NGOs and indigenous peoples, immigrants and refugees who become subjects of adjudication in human rights decisions, human rights and environmental activists, and many others are increasingly becoming actors in global politics. That is to say, non-state actors can enter and gain visibility in inter-national fora or global politics as individuals and as collectivities, emerging from the invisibility of aggregate membership in a nation-state exclusively represented by the sovereign. One way of interpreting this is in terms of a