CMesh: A Polymer-Free Carbon Nanotube Scaffold for Robust TEM Specimen Preparation of Porous Graphene

We present CMesh, a polymer-free carbon nanotube (CNT) mesh scaffold for robust TEM specimen preparation of graphene and porous graphene. Fabricated by simple vacuum filtration, CMesh acts as a porous mechanical reinforcement layer during transfer, avoiding direct contact between graphene and a continuous sacrificial polymer support such as PMMA. Under the optimized condition using 0.5 mL of 0.05 mg/mL CNT stock dispersion, CMesh provides dense suspended pockets as TEM/STEM imaging windows while enabling transfer onto standard low-cost TEM grids. Fresh CMesh-supported pristine graphene shows a STEM-segmented cleanliness of 53 ± 6% without post-transfer cleaning. With CMesh reinforcement, pristine graphene and 2 s O₂ plasma-treated porous graphene show high coverages of 99.4 ± 0.3% and 99.4 ± 0.2%, respectively, on standard 400-mesh Cu grids, reducing grid cost by ∼60-200-fold compared with specialized supports. The resulting specimens support atomic-resolution TEM/STEM imaging, remain structurally stable during in situ heating up to 900°C, and retain large-area integrity after approximately one year of storage.