Synthesis And Properities Of The Water-soluble Conjugated Polyelectrolytes Based On Polycyclopentadithiophene Backbone

As one of the most attractive conductive polymers, Water-soluble conjugatedpolyelectrolytes have received a large amount of attention. This material have lots ofadvantages, such as excellent optical and electrical properties, water-soluble and easy processabilities, and now the conjugated polyelectrolytes have been reported on bio-applications suchas DNA sensor, protein sensor, bio-imaging, as well as optoelectronic applications such asorganic light-emitting diodes, organic semiconductors. Polycyclopentadithiophene and itsderivatives have been applied as novel photoelectrical materials because of their remarkablyoptical and electrical properties, and in this article, we synthesized a novel Water-solubleconjugated polyelectrolyte which based on polycyclopentadithiophene back-bone. And theoptical properties, electrical properties of the polymer was studied, also the polymer is appliedas a sensitive and selective fluorescent probe for heparin detection in aqueous solution.1. The cyclopentadithiophene was chosen as starting material and then the monomer4,4’-Bis(3-N,N,N-trimethylammonium-propyl)cyclopenta[2,1-b;3,4-b’]dithiophene Dibromidewas synthesized via bromination, amination. The structure of all compounds was studied byNMR spectra and mass spectra.2. The poly[(4,4-bis(3’-N,N,N-trimethylammonium) propyl) cyclopentadithiophenedichloride](PT2) film was synthesized by electro-polymerization. And the Electrochemicalworkstation, UV spectrum and scanning electron microscope were used to character theoptical、electrical properties and the microstructure of the PT2film. Results showed that thefilm had good electrochemical activity and water solubility， it can be soluble in polar solventsuch as methanol or water. Also the electrochromism property of PT2film was studied. Whendedoping and doping, the color of the film can change from purple to mazarine, and the PT2film could be used as a electrochromic material.3. The solid PT2was synthesized by oxidative polymerization in chloroform using FeCl3asthe oxidant. PT2was readily soluble in polar solvents such as water, methanol. And theFluorescence spectrometer, UV spectrum and scanning electron microscope were used tocharacter the optical、electrical properties and the microstructure of the PT2. The PT2is applied as a sensitive and selective fluorescent probe for heparin detection in aqueous solution.Upon adding heparin into the aqueous solution of polymer, PT2could bind heparin viaelectrostatic interactions and result in the quenching of emission peaks. Quantitative analysisof heparin shows high selectivity and good linear relationship with a detection limit to0.05μM in HEPES aqueous buffer.