Synthesis and surface activity of high and low surface energy multi-end functional polybutadiene additives

Abstract

We report here the synthesis of well-defined, polybutadiene additives; chain-end functionalised with either multiple fluorocarbon or hydroxyl groups. Additives containing low surface energy fluorocarbon groups were made by end-capping polybutadienyllithium prepared via living anionic polymerisation while a combination of living anionic polymerisation and “click chemistry” was used to make high surface energy, hydroxyl functionalised additives. These synthetic methodologies resulted in a high degree of chain-end functionalisation as determined by ¹H-NMR. The functionalised polybutadiene samples were then blended in low concentration with well-defined (unfunctionalised) perdeuterated polybutadiene to establish their effectiveness as surface modifying polymer additives. Elastic recoil detection analysis (ERDA) revealed that the functional polybutadiene additives were very surface active in spin-cast blended films on silicon substrates. The hydroxyl functionalised polymer segregated strongly to the polymer–silicon oxide interface, whereas the fluorocarbon functionalised additives were found to be in excess at the air interface of the polymer film. The wettability of pure additives on the surface of a silicon wafer and Teflon™ were also determined by static contact angle measurement. We anticipate that these additives could be utilised to disperse and stabilise nanoparticles in nanocomposites, and enhance the adhesion of polybutadiene onto low and high energy surfaces. Investigations into the application of the described additives are ongoing and will be reported at a future date.