Synthesis And Characterization Of Conjugated Polymers Containing Spiro Units

In recent years, conjugated polymers has attracted wide attention because of their specialoptical and electrical properties. Ladder polymers are one important branch of conjugatedpolymers and can be applied to the light-emitting devices, field effect transistors, thin-filmlaser, photovoltaic devices and other fields. In this article, we designed a new synthetic route.A monomer with methoxy functional group was synthesized, which can conduct directlyintramolecular ring-closure after polymerization to get the ladder structure. In this way we canget the ladder polymers with perfect structure.The main contents of this thesis are as follows:1. The m-bromophenol was used as a starting material, and a new monomer A2withmethoxy functional group was synthesized. This monomer have methoxy functional group,which can conduct directly intramolecular ring-closure after polymerization to get the ladderstructure, avoiding reduction or addition reaction in the polymers.2. The monomers containing boronic acid pinacol ester groups (B2, B3) and boronic acid(C2, C3) were used to the Suzuki polycondensation with the compound A2. Then the ringclosure reactions of the resulting polymers were brought out, and the linear andhyperbranched polymers were obtained, respectively. The resulting polymers werecharacterized by GPC, UV fluorescence spectroscopy and TGA. All polymers were readilydissolved in common organic solvents, and exhibited bright blue fluorescence in solution. TheUV-vis absorption and photoluminescence (PL) spectra of the precursor polymers P1, P2andthe ladder-type polymers LP and hp-LP in diluted toluene solution present an significantdifference which can be attributed to the change in the conformation. The absorption andemission peaks of the ladder polymers LP and hp-LP shifted toward low energy. All theladder-type polymers exhibited well-resolved absorption and emission spectra, which istypical for a rigid, planar, one-dimensional π-system. The Stokes shifts of LP and hp-LP are6and3nm, respectively, indicating that such ladder-type polymers are extremely rigid. Thethermal properties of polymers were investigated by thermogravimetric analysis (TGA), and polymers LP and hp-LP all exhibit very good thermal stability, undergoing less than5%weight loss up to435oC, and loss of about50%of its weight at about700oC.