Self-Organization and Dynamics of Nanoflakes in Nanochannels

This study investigates the self-organization and dynamic behavior of square-shaped nanoflakes confined between rigid planes, with and without liquid, to elucidate their critical role in nanochannel applications. Employing molecular dynamics (MD) simulations at room temperature, we analyze four distinct setups: (1) freely floating flakes, (2) freely floating flakes with liquid, (3) flakes confined in a 3 and 4 nm gap without liquid, and with liquid (4). Complementing these simulations, experimental observations using glass micropipettes filled with 2D silver flakes, analyzed via scanning electron microscopy, reveal preferential wall adhesion, the formation of dense boundary layers, and flake-depleted core regions. These findings align closely with MD results, highlighting how liquid-mediated interactions profoundly influence flake adsorption, stability, and self-assembly. By introducing an effective potential including two terms, the wall potential (<i>U</i>_wall) drives flake attachment to the planes, while the pairwise interaction potential (<i>V</i>_<i>ij</i>) governs flake-flake alignment. Increasing the liquid-liquid interaction strength (ε) from 0.24 to 0.9 kcal/mol enhances in-plane rotational dynamics while preserving perpendicular alignment, driven by a synergy of van der Waals and capillary forces. Conversely, reducing the nanochannel height from 4 to 3 nm diminishes liquid effects, amplifying flake-plane interactions and reshaping self-assembly patterns. These insights bridge microscale experimental observations with nanoscale dynamics, offering a deeper understanding of nanochannel behavior and paving the way for innovative applications in nanofluidic transport.