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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 23: Interfaces and Thin Films III
CPP 23.2: Talk
Tuesday, April 1, 2014, 15:15–15:30, ZEU 114
Optically triggered release from a molecular container: Photoswitching in thin films of metal-organic frameworks — •Lars Heinke1, Murat Cakici2, Stefan Bräse2, and Christof Wöll1 — 1Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Karlsruhe — 2Institute of Organic Chemistry (IOC), Karlsruhe Institute of Technology (KIT), Karlsruhe
The remote control of surface properties is one of the key challenges in interfacial science. Here, we are going to show the great potential of thin porous films of metal-organic frameworks (MOFs) containing linkers with photoswitchable azobenzene side groups. The state of the azobenzene side groups can be switched by UV light from trans to cis and vice versa by visible light. This photoswitching influences the mass transfer of the guest molecules in the pores, i.e. the pores are ideally opened and closed by light. By means of liquid-phase epitaxy, SURMOFs (surface mounted metal-organic framework) with vertical compositional gradients can be synthesized. This enables the preparation of thin porous films with a passive bottom layer, which serves as a storage container, and a photoswitchable top layer serving as a valve, which opens and closes the container. After loading the porous coating with guest molecules, its release is initiated by illumination with visible light and monitored by a quartz crystal microbalance (QCM).