Polymerization-Induced Nano-Order, Ordered Melt, Chain Explosion and Meso-Superstructures of E-Polyethylene

During the past 70 years, it has been well established that melts of crystalline homopolymers adopt disordered random coil conformations and are densely packed in globules above the melting temperature ( T _m ). Flow-induced melt orientation promotes crystal nucleation and polymorphism upon cooling. Here, we present polymerization-induced nano-to-mesoscale condensed-ordering as well as order-to-order and order-to-disorder (O-D) melt transformations at T _O-D in engineering polyethylene (E-PE). Moreover, we demonstrate fast chain explosion and re-entanglements at T _O-D . Liquid-crystalline-like macroscale 2D-ordered nanofibrils and meso-ordered superstructures self-assemble from high-order condensed states and ordered melts via isothermal crystallization, respectively. Self-reinforced optical and shape memory sheets are made by preserving nascent meso-ordering. Eplastomers, which exhibit both elastomeric and soft‒plastic properties, are prepared by nano-fibrillation of non-crosslinked E-PE meso-particles in a polyolefin elastomer matrix and dynamic exchange of 1D-ordered nanofibrillar networks with disordered 3D meso-granules. These findings enable further development of ultrahigh-performance intelligent, photonic and sustainable polymeric materials.