The ability of block copolymers (BCPs) to spontaneously microphase separate and self-assemble into well-defined nanostructures having periodicities in the range of 5 nm – 100 nm makes them highly attractive as potential candidates for next-generation applications including lithography, thin film filtration membranes and nanoelectronic devices such as capacitors, batteries and photovoltaics. Directing the self-assembly of high-interfacial area lamellar-BCP (l-BCP) nanodomains in thin films to produce vertically oriented etchable nanostructures holds much technological relevance for potential device manufacturing applications. Previously we investigated vertically assembly of cylinder c-BCP and nanoparticle induced vertical assembly of l-BCP. In this work, we demonstrate a template-free approach towards rapid (2 – 4 min.) fabrication of highly ordered vertical lamellar microdomains in l-BCP thin films (100 nm – 1 μm) by a one-step continuous dynamic thermal gradient process – Cold Zone Annealing-Sharp (CZA-S). CZA-S creates a thermal gradient induced strain gradient field that directs the self-assembly of l-BCPs to create vertically oriented lamellar microdomains without resorting to complex, expensive and time-consuming techniques. The facile CZA-S process has the potential for continuous large-area manufacturing of highly ordered nanomaterials on rigid as well as flexible substrates due to its inherent compatibility with the existing roll-to-roll technology. This study also reports a thorough understanding of the dynamic molecular mechanisms involved in the nanostructure formation and morphology evolution of vertically oriented BCP lamellae along the CZA-S thermal gradient tracked in real-time by in-situ Grazing Incidence Small Angle X-ray Scattering (GISAXS) studies.

Vertically oriented block copolymer thin film by dynamic thermal field directd self-assembly

255th National Meeting (2018)

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