Nitrogen trioxide, reaction with structure

Polycarbonate is a thermoplastic material used in many applications, including microchips. The aromatic rings in the polycarbonate structure offer a relatively easy way to modify the PC surface by a direct sulfonation reaction. After cleaning with isopropyl alcohol, the polycarbonate surface is modified by reaction with sulfur trioxide at 50 °C for 10 min. Then it is rinsed with water and dried in a stream of nitrogen. 

---