Measurement of sliding friction coefficient of micro-line patterned surfaces on ice

Abstract

Although the sliding friction of patterned surfaces on ice has been investigated for over a century, physical analysis still needs to be improved. In this study, we investigate the friction coefficient on ice by changing the experimental conditions of temperature, gap between line patterns (20 μm and 200 μm), and sliding direction. In the temperature region of −17.7 °C < T <−2.5 °C, a longer gap (200 μm) patterned surface has a lower friction coefficient for both parallel and perpendicular sliding directions at the same temperatures. Interestingly, a lower friction coefficient is found when the sliding direction is perpendicular to the micro-structure patterns at T < −7.6 °C for gap = 20 μm and at T < −9.9 °C for gap = 200 μm. To understand this interesting phenomenon, a theoretical model is derived by modifying the model from the study by Oksanen and Keinonen. Based on this modified model, the surface with a shorter gap (20 μm) makes fewer contacts and the pattern direction determines the water layer elongation at each contact. This validates that friction on ice can be controlled using a micro-structure pattern and moreover suggests a method for finding an optimized micro-structured surface for reducing friction on ice.

Extracting Polaron Recombination from Electroluminescence in Organic Light‐Emitting Diodes by Artificial Intelligence

“…[9][10][11] For the polaron dynamics, the frontier orbital levels of the charge transport layers and charge balance in the emitting layer (EML) significantly contributed to the formation of the recombination zone, resulting in different operational stabilities. [12,13] Polaron transfer between the host and dopant molecules in the EML was proven to accelerate the degradation of materials. [14][15][16][17] Specifically, the excitoninduced polaron pair and dopant-induced trapped polarons were highlighted as the main contributors to luminance quenching during the operation.…”

Surface Hierarchy: Macroscopic and Microscopic Design Elements for Improved Sliding on Ice

“…The smallest plateau was found on the 50 µm laser-grooved block, as seen by the smallest encompassing ellipse that shows the 1 µm top-layer; the 100 µm wide grooved block exhibited a more elongated 1 µm top-layer, but the block with 150 µm grooves showed the largest top 1 µm contact footprint. Since larger contact areas are associated with more friction [21,27,28], then the initial intuition could be that the last block would have the slowest sliding speed. Reports on the sliding speed, however, indicated the opposite trend.…”

Sliding friction of hierarchically micro–micro textured polymer surfaces on ice

“…Textures can be formed by adding, removing, or displacing material (Coblas et al, 2015). The effects of surface textures on ice friction have been studied both via simulations (Costagliola et al, 2016) and experimentally (Anwer et al, 2017;Colonna et al, 2016;Ella et al, 2013;Isomaa et al, 2015;Kietzig et al, 2009;Kim et al, 2017;Rizvi et al, 2015;Stamboulides et al, 2012). Friction can be controlled by adjusting the orientation of the surface texture in relation to the direction of the sliding movement, depending on the dominant lubrication regime at play (Kietzig et al, 2009;Kim et al, 2017;Stamboulides et al, 2012).…”