Photon-assisted displacement of directionally freeze-dried symmetric graphene aerogels
Omar Khattab, Rami Elkaffas, Basel Altawil, Carlo Saverio Iorio, Shan-Min Swei, Yarjan Abdul Samad
Abstract
Photon-assisted displacement of low-density materials such as graphene-based aerogels has been demonstrated. This study represents a comprehensive investigation into the photon-assisted displacement of graphene aerogels using a state-of-the-art experimental setup in vacuum. The study examines how altering the microstructure and pore alignments in a graphene aerogel by directional freezing affects photon-assisted displacement. Directional freezing introduced uniform, porous, directionally aligned structures. Aerogels possess a aligned-lamellar structure. An aerogel of density mg/cm 3 has an average aligned-lamellar layer spacing of 160 µ m. Scanning Electron Microscopy (SEM) revealed significant impacts of freezing techniques on the microstructure, e.g., layer spacing, thus influencing the performance of photon-assisted displacement. An aerogel with high density, directionally frozen with Liquid Nitrogen (LN) and tested under a vacuum of Torr, exposed to the highest laser power (3.5 W), exhibited a thrust of 36 µ N. A rigorous 2D-SEM analysis framework was applied to extract four quantitative descriptors—porosity ( ), pore-size distribution, lamellar spacing ( ), and anisotropy reprented by orientation order parameter. Statistical correlation of these descriptors with measured thrust performance provided mechanistic insight into the photon-assisted displacement process. To the best of our knowledge, this is the highest thrust achieved in comparison to laser displacement of graphene-related materials (GRMs). The displacement efficiency depends on the vacuum level, the aerogel densities, the laser power, and the freezing techniques. • Demonstrated record photon-assisted displacement in directionally frozen graphene aerogels. • Displacement efficiency increases with vacuum, density, and laser power. • Directional freezing produces nacre-like microstructures affecting thrust performance. • Achieved highest reported thrust for graphene aerogels under laser irradiation. • Findings have implications for micro-scale propulsion in space technologies.