Charge carrier mobilities in (partially) polymerised diacetylenes using a pulse radiolysis microwave conductivlty technique

Abstract

Summary form only given. Urethane substituted diacetylenes C/sub 4/[(CH/sub 2/)/sub n/OCONHCH/sub 2/COOC/sub 4/H/sub 9/]/sub 2/ (nBCMU) can be solid-state polymerised to high molecular weight polymer by high energy irradiation [1]. We have followed the change in conductive properties as polymerisation proceeds using the contactless pulse-radiolysis time resolved microwave conductivity (TRMC) technique [2]. With this technique we can study the conductivity of the polymer backbones unperturbed by the effects of domain boundaries or chain to chain transfer [3]. We find that the conductivity in the 3-, 4- and 9BCMU samples increases linearly with monomer to polymer conversion. The charge carrier mobilities within the polymer backbones were determined to be at least 10 cm/sup 2//Vs. Conductivity studies using the TRMC technique have also been carried out on 100% thermally polymerised single crystals of bis-p-toluenesulphonate diacetylene (PTS). A similar charge carrier mobility of at least 7 cm/sup 2//Vs was found. Additional evidence for charge transport along the polymer backbone was provided by an anisotropy ratio of 160 in favour of the conductivity in the direction of the backbones.