Reactivity of poly(dimethylsiloxane) toward acidic permanganate

Poly(dimethylsiloxane) (PDMS) has been widely used in various microfluidic devices because it is considered to be one of the most inert materials available. A PDMS-based microfluidic system for the synthesis of manganese oxide (MO) nanoparticles is developed and tested. However, synthesis of MO nanoparticles in the PDMS-based microfluidic system is unsuccessful due to an unexpected reaction between acidic permanganate and PDMS. PDMS is pitted and coated with MnO2 and opalized silica, which are confirmed by SEM and EDX. The products of the reaction between PDMS and acidic permanganate are mainly MnO2, Cl2, SiO2 and CO2, respectively. Here we report for the first time the reactivity of PDMS toward acidic permangante resulting in a new process to coat the channel walls with MnO2.