Nanostructured proton conducting polystyrene - poly(vinylphosphonic acid) block copolymers prepared via sequential anionic polymerizations

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Abstract

Poly(styrene-b-vinylphosphonic acid) diblock copolymers have been prepared via sequential anionic polymerization and evaluated as nanostructured polymer electrolytes. The ionic block copolymers were synthesized by first initiating the polymerization of styrene using n-butyllithium in tetrahydrofuran at −78 °C. 1,1-Diphenylethylene was then added to the living polystyryl anions before charging diethyl vinylphosphonate to polymerize the second block. The poly(diethyl phosphonate) block was subsequently completely hydrolyzed to obtain the poly(vinylphosphonic acid) block. Analysis by calorimetry showed two distinct glass transitions of the acidic copolymers, indicating phase separation between the two blocks. The glass transition temperature of the densely phosphonated blocks was strongly influenced by the formation of anhydride links through reversible self-condensation reactions at elevated temperatures. Studies of thin copolymer films by tapping mode atomic force microscopy revealed nanophase-separated morphologies with continuous phosphonated domains. In addition, the acidic block copolymers were found to self-assemble into spherical micellar nanoparticles which, in turn, formed branched arrays of supramolecular “necklace-like” chain structures. Block copolymers equilibrated at 25 °C and 98% relative humidity reached proton conductivities in the order of 30 mS/cm at 130 °C.

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  • Chemical Sciences
Original languageEnglish
Pages (from-to)5146-5154
JournalMacromolecules
Volume42
Issue number14
Publication statusPublished - 2009
Publication categoryResearch
Peer-reviewedYes

Bibliographic note

Publication Date (Web): June 5, 2009 The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Polymer and Materials Chemistry (LTH) (011001041)