Low Molecular Mass Gelator Assisted Gelation of Conductive Polymers

Combining the electrical and mechanical properties of conductive polymers with synthetic scaffolds such as hydro/organo gels is an attractive approach for the design of soft materials for potential biomedical and engineering applications. Here, we report gelation of a conductive polymer, poly(3-hexylthiophene), in the presence of a low molecule mass gelator, Di-Fmoc(Lys). The gels were formed by a temperature-triggered method in chloroform. UV−vis spectroscopic analysis provided an insight into the photophysical response of the gelation process. A nano-fibrillar microstructure for both pristine Di-Fmoc gel and P3HT containing Di-Fmoc gel (hybrid gel) has been captured using atomic force microscopy. The self-assembly of Fmoc and P3HT molecules has been confirmed using GIWAXS. The rheological properties of pristine and hybrid gels have been found to be similar. Conductive AFM study captures the conductive P3HT domains in the gels. The conductivity of dried gel films was measured and was compared with that of dried P3HT thin films. Both these samples displayed a similar level of conductivity despite having a much lower concentration of P3HT in the dried gel films. It has been hypothesized that P3HT in hybrid gels formed a percolated network in the gel, which was maintained during the drying process. This thermoreversible gel framework has also been extended for other semiconducting polymers and in non-halogenated solvents. Our technique can be utilized for large-scale thin films/coatings in optoelectronic applications.