Selenophene and Thiophene-Based Conjugated Polymer Gels

Conjugated polymer gels are promising materials that are intrinsically stretchable and conductive, which may play an important role in the development of stretchable electronics. In this work, a series of thiophene and selenophene-based conjugated polymers with similar molecular weight and low dispersity were synthesized and the gelation conditions of these polymers were studied. The electrical performance of both thin and bulk films of these conjugated polymer gels were investigated. Blade-coated gels that form the highest quality films can achieve a similar charge carrier mobility as a spin coated sample, showing that gels are indeed promising electronic materials. The most promising gels were studied as a stretchable device. The initial application of strain appears to lead to the lower mobility; however, the device stabilizes and retains the same mobility from 18% to 40% strain. Finally, a new cycle-doping method was developed to successfully dope the bulk gels to yield conductive films. This method allows one to monitor the changes in conductivity as a function of doping to ultimately achieve the highest conductivity. The cycle-doping method appears to be superior to the commonly used dip-doping method. Overall this work expands on the types of conjugated polymers gels that are useful for electronics, stretchable electronics, and conductive materials.