2023/11/09 by Jaehyung Yu, Colin Scheibner, Yu, Jaehyung +9
Engineering · #Advanced Materials and Mechanics #Advanced Sensor and Energy Harvesting Materials #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Modular Robots and Swarm Intelligence
paper · pdf · doi:10.48550/arxiv.2311.05096
openalex publication_date 2023/11/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Atomically thin films, like transition metal dichalcogenides, can now be synthesized at wafer scale, achieving the same extreme aspect ratio (~108) that a sheet of paper would have if it covered an entire city. Yet, the intrinsic (i.e. unconfined) three-dimensional shape of these extreme membranes remains a mystery because of the very fundamentals of mechanical measurements: to measure such an ultra-thin film, one first needs to simultaneously free it and stabilize it without introducing confining boundaries. Here, we introduce a counter-intuitive solution to this problem: place atomically thin films on water. Using atomic force microscopy (AFM) and Raman spectroscopy adapted to water's surface, we reveal that large-scale freestanding membranes spontaneously self-wrinkle into a universal mechanical state with long emergent length scales that follow robust scaling trends. Our analytical and numerical models suggest that these universal trends are controlled by mesoscopic parameters of the polycrystalline domains instead of atomistic details. Moreover, we demonstrate experimentally that the wrinkles result in a large and tunable reduction of elastic stiffness by up to 2 orders of magnitude. The present work illuminates the physical properties of the world's thinnest materials at length scales never probed before and highlights their potential for tunable strain-controlled nanomechanical devices.