Topochemical polymerization of diacetylenes

Abstract

Since the discovery of conducting polymers, they have received considerable attention both from academic and industry due to their attractive advantages of light weight, low cost, and easy processing, which make them demonstrate a wide range of applications. Over the past decades, significant advances have been achieved in this field with the development of high performance polymeric semiconductors and device fabrication techniques. However, there are still many scientific questions existing in this field, such as the unclear charge transport physics in conjugated polymers due to disordered molecular structures in the widely investigated films. Compared to thin films, single crystals possess long-range molecular order, no grain boundaries and no defects, which are seen as the best candidates for revealing the intrinsic charge transport of materials. However, it has been a big challenge for the crystallization of polymers directly from solution, and even is elusive for the conjugated polymers due to their intrinsic electron-rich conjugated backbone structures. Topochemical polymerization where under a certain reaction condition, the preorganized monomer crystals could be directly changed to their corresponding polymer crystals with a minimum amount of atomic and molecular movement, that is realizing the single-crystal-to-single-crystal transformation would provide us a promising solution. Compared to traditional solution process, with this method, we can possibly realize two goals: (1) the controllable synthesis because the first crystal growth process is from the monomer molecules; (2) the possible obtainment of higher molecule-weight polymer chains because we do not need consider their solubility problem like that from solution synthesis.