Direct SN1 reaction at oxidized PPF surfaces

- PPF samples prepared under a non-reductive Ar atmosphere present -OH terminations.
- Electron transfer kinetics for ferricyanide and dopamine are retained or improved.
- A facile SN1 reaction between the oxygen-rich surface and ferrocenemethanol is achieved.
- This surface functionalization procedure yields a sub(monolayer) of ferrocenyl units.

For comparative purposes, two series of pyrolyzed photoresist film (PPF) substrates are prepared with and without reductive conditions, i.e. in the presence and absence of H2. Electrochemical and X-ray photoelectron spectroscopy analyses show that PPF substrates prepared in the absence of H2 possess many more surface oxygen functional groups, mostly hydroxyl groups, than PPF prepared under reductive conditions. These oxidized PPF samples can be advantageously involved in an SN1 reaction to covalently bind ferrocenyl groups to the surface as (sub-)monolayers.