Novel polyviologens: Photochromic redox polymers with film‐forming properties

Several novel polyamides containing the N,N′‐dialkyl‐4,4′‐dipyridinium (“viologen”) system were made by interfacial condensation of N,N′‐bis(aminoalkyl)‐4,4,‐dipyridinium salts with di‐, tri‐, or tetrafunctional acid chlorides. These materials are useful redox polymers which turn deeply colored when reduced chemically or electrically, or when exposed to light.