Stabilization of the Fluorescent Polymer Containing Thiophene in the Sodium Deoxycholate Gel and Determination of the Mobility of Small Molecules in this Polymer-Gel System

Abstract

Conjugated polymers have interesting luminescent properties and have applications such as for diodes, sensors, and optoelectronic devices. However, copolymers containing thiophene moieties can suffer from photodegradation and can have low solubility in aqueous solvents. The bile salt sodium deoxycholate (NaDC) is a biological surfactant that is able to form supramolecular hydrogels through the presence of different noncovalent interactions. On the other hand, photochromic molecules, such as azobenzenes, have the capability to reversibly change optical properties with irradiation of light at different wavelengths. The photoisomers have different shapes and the mobility of the different isomers through the gel will determined. In this context, the present work involves the capability of the NaDC gel to solubilize and stabilize a conjugated polymer, the poly(3-hexylthiophene-co-1,4-phenylene) (PTPh) and the use of azobenzenes containing three different charges (positive, neutral and negative) will be used to measure the mobility of these compounds in the PTPh-NaDC gel. The mobility of the azobenzenes will be related to ability of the azobenzenes to quench the emission of the conjugated polymer.