Nianxing Wang dissertation
The public defense of MSc Nianxing Wang took place in Arcanum, in the Chemistry building on 14th of October 2016. The thesis work has been carried out in the Laboratory of Materials Chemistry in the group of Professor Carita Kvarnström. Professor Barbara Pałys from University of Warsaw acted as opponent.

In his thesis work Nianxing Wang focused on polyviologen materials. What are viologens? The general name of viologens is 1,1´-disubstituted-4,4´ -bipyridinium salt, which is one of the most widely used active organic material in different  electronics especially in electrochromic devices (ECDs) and sensors. Their unique redox properties, excellent stability, variety of colors and special structures, have inspired their application in many different fields of research.  The redox processes enable the viologens to work as mediators in sensors or biosensors and their switching between the differently colored redox states makes them suitable as electrochromic materials in ECDs. Furthermore, the reductive potential enables them to work as catalyst for reduction reaction of different materials such as carbon nanotubes and graphene.

In this work, several crosslinked polyviologen and copolyviologen films were synthesized elecrtrochemically from different, in the group synthesized cyanopyridine based precursor materials. The cavity size of the films could by the use of different substituted cyanopyridine monomers be adjusted showing potential for such polyviologen films as immobilization materials. Furthermore the good stability and reversible redox processes of the films enables them to be used as mediators in sensors and in fuel cells. 

Professor Barbara Palys, Nianxing Wang and Professor Carita Kvarnström