Chameleon Molecules: Imidazole Functionalized Poly(3-hexylthiophene) (P3HT) Properties and Integration in Alginate Hydrogels

Poly(3-hexylthiophene-2,5-diyl) (P3HT) is a polymer that has been heavily studied for its application in photovoltaic cells. Here we seek to develop new biological uses for this polymer. Using Kumada coupling and Soxhlet extraction we have synthesized P3HT polymers functionalized with imidazole groups, deemed P3HT-Im, with varying molecular weights. The physical properties of long, medium, and short length variations of these polymers have been investigated using carboxymethyl cellulose, carboxymethyl amylose, and sodium dodecyl sulfate. The polymers in conjunction with sodium dodecyl sulfate red shift under the critical micelle concentration. Upon reaching charge neutrality a coacervate forms. Above the critical micelle concentration micelles form, shown by dynamic light scattering, and solutions blue shift. Unlike with SDS, polymers with CMA or CMC blue shift or red shift respectively up to a maximum concentration where changes in fluorescence no longer occur. Visible induced color changes of the solutions occur for each polymer and each binding unit, also apparent under UV light. The polymers ability to cause blue shifts and red shifts in solution depending on the compound they interact with, the concentration, and the number of repeat units allows for a wide variety of applications. Recently the polymers have been incorporated into alginate hydrogels to investigate timed release of the polymer and biocidal capabilities of the gels.