Meniscus-Guided Soft-Lithographic Assembly of Grid-Type Molecular Martensite Films for Single-Crystal-Like Actuation

초록

Dynamic molecular martensites exhibit large, reversible deformations and high force densities. However, device integration has been limited by the brittleness and poor formability of single crystals. Here, we report a thin-film route that translates molecular cooperativity into processable actuator architectures while preserving directional deformation. Meniscus-guided printing is combined with microtransfer molding to fabricate two-dimensional grid actuators of 6,13-bis(triisopropylsilylethynyl)pentacene. A partial drag-out regime in microchannel molds delays crystallization and enables seed-mediated sequential growth across intersections between horizontal and vertical microchannels. This mechanism produces a preferred b-axis-correlated preferential texture across the grid, with the crystallographic b-axis nearly aligned with the printing direction while allowing a small in-plane offset in twin-related variants. This texture provides the structural basis for predictable deformation comparable to that in single crystals. The resulting films are ultrathin, transferable over centimeter-scale areas, and mechanically robust, reproducing large thermoelastic strain and withstanding repeated actuation cycles without loss of performance. Beyond simple elongation, multi-unit assemblies can be constructed to achieve compression, demonstrating how different spatial arrangements enable various modes of actuation. Thus, this study bridges molecular-scale cooperativity and thin-film manufacturability, and provides an extendable strategy for translating thermally stable, solution-processable dynamic crystalline materials into functional, transferable, and microstructured actuator platforms.

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