Guided motion of Fullerene-Wheeled nanomachines on gradient gold Pathways: A molecular dynamics study

• Conducted comprehensive molecular dynamics simulations of fullerene–wheeled nanomachines (C 36 –C 90 ) moving across gradient–engineered gold pathways on silver substrates. • Identified negative–gradient (NG) topographies as enablers of up to 20% greater displacement and ≥ 0.02 Å 2 /fs diffusion, demonstrating superior nanoscale transport efficiency. • Revealed that C 60 is optimal in only ∼ 10% of conditions, while C 36 dominates efficiency in ∼ 33%, emphasizing design diversity beyond canonical models. • Showed gradient landscapes (NG + ZG) deliver optimal mobility in > 70% of nanomachine–temperature combinations. • Established explicit design principles linking wheel size, surface gradient, and temperature for high–stability, directed nanoscale motion-guiding future nanorobotic and NEMS applications. Overcoming thermal fluctuations is a fundamental challenge in achieving directed motion for nanomechanical systems. Fullerene-based nanomachines have been investigated for their potential to harness thermal energy for directed transport. While studies have primarily focused on uniform pathways, the intricate interplay between pathway geometry, fullerene size, and the resulting navigational efficiency remains a critical area requiring deeper exploration. This research employs extensive molecular dynamics simulations to scrutinize the locomotion of nanomachines featuring fullerene wheels ranging from C36 to C90. The simulations were conducted on gold substrates engineered with three distinct topographical configurations: a non-sloped planar surface, a surface with a positive topographical gradient, and a surface with a negative topographical gradient. Our findings reveal a significant correlation between pathway geometry and nanomachines performance. Specifically, nanomachines exhibited markedly more rectilinear trajectories and enhanced angular stability when navigating pathways with a negative topographical gradient. Conversely, pathways with a positive gradient impeded directed motion, leading to increased diffusive behavior. Furthermore, the size of the fullerene cage played a pivotal role in determining the optimal operating conditions. Larger fullerene wheels, such as C80, demonstrated superior performance at lower thermal energy regimes, while smaller fullerene wheels, exemplified by C36, were more efficient at higher temperatures. Intriguingly, the commonly utilized C60 fullerene demonstrated optimal performance in only approximately 10% of the simulated scenarios, whereas C36 achieved optimal efficiency in about 33% of cases. This underscores a critical paradigm shift, suggesting that fullerene size selection for nanomachinery applications should transcend conventional choices and be carefully tailored to the intended operational environment. In conclusion, the strategic optimization of substrate topography, particularly the implementation of negative gradients, presents a potent methodology for enhancing directed nanoscale transport. These empirical insights derived from rigorous simulations offer valuable guidance for the rational design of advanced molecular pathways and nanomachines with improved functionality for a wide array of nanotechnological applications.