Homologous Series of Polyaniline Derivatives Block Copolymers with Amphiphilic and Semiconducting Properties

Semiconducting polymers with amphiphilic properties can play an increasing role in future organic and unimolecular electronic devices, especially due to their excellent processability and ease of self-assembly into thin films, but they could also be used as intermediate layers to improve electron transport in metal-organic junctions. In this work, we synthesized a homologous series of amphiphiles by copolymerization of aniline with aniline-N-propanesulfonic acid. The polymerization was first initiated with aniline, and the latter monomer was added at different time intervals: 2, 10, 20, 30, 40, and 60 min, spaced from the time of initiation. Thus, the poly(aniline-co-aniline-N-propanesulfonic acid) (PANi-co-PANs) homologous series of copolymers obtained had the same length of the water soluble PANs chain, and a variable length of the water insoluble PANi chain. We demonstrated that there is a strong structure-activity relationship in the homologous series of PANi-co-PANs copolymers, evidenced in the tensiometry and wettability studies, as well as in-depth conductivity with frequency and temperature investigations. We observed a gradual change in solubility, interfacial activity, and conductivity in the homologous series of amphiphiles within the boundaries set by the electrically insulating, hydrophilic PANs chain and the semiconducting, hydrophobic PANi chains; representing a viable platform toward designing polymers with tunable conductivity.