3-D (nanoscale) Local Near-Field Mode Initiated Polymerisation at Mesporous Interfaces

• Applicant: Professorin Dr. Annette Andrieu-Brunsen
• Subject Area: Polymer Materials
• Term: since 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 280027530

Transport through mesopores is performance-limiting in many technologies such as water- and energy management. Based on the increasing relevance of these technologies an increasing importance of mesopore transport design is envisioned. Biological pores demonstrate very sophisticated and precise transport control as compared to technological pores. To design transport rates and to direct transport in technological materials precise nanoscale placement of (responsive) functions (gradients, gates) together with flexibility regarding selected functions is required. Inspired by the vision of directed selective transport in mesopores the presented project aims to nanolocally graft responsive polymers into ceramic mesopores and direct transport along such responsive nanoscale gradients. The essential step towards this vision, nanolocally limited polymer grafting, is systematically investigated and achieved by near-field mode initiated polymerization. Besides nanolocal placement the near-field mode wavelength (usually >400 nm) is a challenge. Although, visible light initiated polymerizations are currently intensively developed only few examples of near-field mode initiated polymerizations have been demonstrated. These are initial proof of concepts based on plasmonic nanoparticles and commercial resists. Polymerization control as well as resulting material function are neglected. During the first funding period we optimized mesoporous film preparation regarding compatibility with surface plasmon excitation, systematically investigated dye-sensitized polymerization at 532 and 633 nm, and tested vis-iniferter initiated polymerizations in a very first experiment. In addition to near field modes at planar metal films we developed plasmonic nanoparticles embedded mesoporous films and demonstrated nanoscopically limited polymer functionalization of mesoporous films. Based on these results we intend to design nanoscale responsive gradients and orthogonally responsive, nanoscale gates and correlate localization and type of polymer to the resulting transport characteristics. This will be based on the extension of near-field mode initiated polymerizations towards a flexible technology platform for nanolocal mesopore functionalization including controlled VIS-Iniferter initiated polymerizations. Near-field mode induced polymerization at planar metal films will be used to investigate transport direction of nanoscale gradients. Plasmonic nanoparticles will be used to design nanoscale gates. Weak polyelectrolytes responding to pH or redox stimuli will be applied for gradient and orthogonally responsive nanogate design as well as Block-cooligomers allowing to precisely adjust hydrophobicity and charge even further improving transport direction and selectivity. This technological platform is of relevance in various fields such as sensor development, combination with other high resolution optical techniques or application for designing complex, compartmentalized systems.

• DFG Programme: Research Grants