Controlling nanoscale structure and function is highly important for the fabrication of functional materials which are used, for example, in sensing, separation, or drug delivery. Whereas the structure of nanopores and -channels can be well controlled through self-assembly or track etching processes, the controlled functionalization remains a challenge. In recent years it has been demonstrated that photoiniferter initiated polymerization (PIP) offer the possibility to adjust the polymer amount and with this ionic permselectivity in mesoporous membranes. Based on results on zwitterionic polymers rendering mesopores bipolar and thus inaccessible to ions and calculations on charge transitions of poly(2-(methacryloyloxy)ethyl-phosphat (PMEP) in spatially confined pores, the question about the polymer chain architecture influence on mesopore performance attracted our interest. In this frame we present results on the functionalization of silica mesopores with block-co-oligomers using PIP (Fig. 1). Suitable candidates of interest to modulate charge density in mesoporous polymerhybrid films and thus to control their ionic permselectivity is the polyacid PMEP as well as the 2-dimethylaminoethylmethacrylat (DMAEMA)-co-MEP block copolymer. In contrast to solution but in accordance to molecular theory we only observe one pKs value for PMEP confined into mesopores. In addition, chains in a block like architecture induce a different pH-responsive mesopore accessibility as compared to zwitterionic polymers. Results on ionic permselectivity are obtained by cyclic voltammetry for mesoporous films of varying pore sizes in dependence of solution pH. We currently work on comparing those results with spectroscopic investigations of “pH” in spatially confined mesopores using pH-responsive fluorescence dyes.

Influence of chain architecture on transport properties in polyelectrolyte functionalized mesopores

256th National Meeting (2018)

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