Immobilization of Hydrogen-Bonded Capsules on Silicon Wafer

• Applicant: Dr. Sebastian Richter
• Subject Area: Organic Molecular Chemistry - Synthesis and Characterisation
• Term: from 2014 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 259032434

In this project, we are aiming at the immobilization of hydrogen-bonded capsules on silicon wafers and explore the physical organic and material properties of these molecular architectures with purpose to develop drug-delivery systems and supramolecular Velcro. We will synthesize cavitands with alkene feets which can self-assemble into capsular structures templated by a variety of guest molecules. The terminal alkenes are well suited for a photochemical or thermal deposition of the cavitands on hydrogen-terminated silicon through hydrosilylation. For the characterization and study of the modified surface and capsule self-assembly we will use multiple surface analysis methods as well as the encapsulation-enabled fluorescence turn-on properties of guest 4,4-dimethylbenzil. The capsular structures used here are held together by very strong hydrogen bonds and can even survive in water. Therefore, this system may be well suited to a drug-delivery system for appropriate shaped drug molecules which fit into the capsule`s cavity. Meanwhile, a supramolecular Velcro can be constructed from an inter-surface capsule self-assembly and this system may survive in vacuum, air and a variety of solvents and thus finds broad applications. In addition, the capsule formation is strongly dependent on the template effect of guests. Therefore, the strength of this supramolecular Velcro may be well tuned by using different guest molecules. For example, a photo-switchable guest, such as 4,4-dimethylazobenzene, may even endow the supramolecular Velcro with photoswitchability. Therefore, we believe the research in this project will open new frontiers for applications of surfaces modified by supramolecular architectures.

• DFG Programme: Research Fellowships
• International Connection: China
• Host: Professor Dr. Wei Jiang