Braided channel networks exhibit a complex interplay between spatial and temporal dynamics. Their behavior is characterized by both simple and multiscaling patterns, and the mechanisms underlying the stochastic processes associated with this dynamics remain incompletely understood. Leveraging Taylor's pioneering work [Nature (London) 189, 732 (1961)NATUAS0028-083610.
View Article and Find Full Text PDFWetting is often perceived as an intrinsic surface property of materials, but determining its evolution is complicated by its complex dependence on roughness across the scales. The Wenzel (W) state, where liquids have intimate contact with the rough surfaces, and the Cassie-Baxter (CB) state, where liquids sit onto air pockets formed between asperities, are only two states among the plethora of wetting behaviors. Furthermore, transitions from the CB to the Wenzel state dictate completely different surface performance, such as anti-contamination, anti-icing, drag reduction etc.
View Article and Find Full Text PDFEur Phys J E Soft Matter
February 2020
We derive approximate mean field equations for the fluid flow between elastic solids with randomly rough surfaces including interfacial fluid slip and shear thinning. We present numerical results for the fluid flow and friction factors for realistic systems, in particular, we consider the case of an elastic cylinder with random surface roughness in relative sliding contact with a flat rigid (low-energy) counter-surface. We present experimental data for the sliding friction between rubber stoppers and glass barrels lubricated with baked-on silicone oil.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2018
The understanding and control of human skin contact against technological substrates is the key aspect behind the design of several electromechanical devices. Among these, surface haptic displays that modulate the friction between the human finger and touch surface are emerging as user interfaces. One such modulation can be achieved by applying an alternating voltage to the conducting layer of a capacitive touchscreen to control electroadhesion between its surface and the finger pad.
View Article and Find Full Text PDFAnisotropic friction plays a key role in natural systems, particularly for realizing the purpose of locomotion and strong attachment for the survival of organisms. Of particular interest, here, is the observation that friction anisotropy is promoted numerous times by nature, for example, by wild wheat awn for its targeted and successful seed anchorage and dispersal. Such feature is, however, not fully exploited in man-made systems, such as microbots, due to technical limitations and lack of full understanding of the mechanisms.
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