Ultrastable Oleophilic PTFE Channel with Wedge Arrays by Femtosecond Laser for Self-Transport of Oily Droplets in Harsh Environments
Despite significant advances in oil transport, existing channels remain susceptible to chemical corrosion, resulting in material degradation and eventual functional failure. Here, a biomimetic two-order wedge channel (TOWC) is presented that combines the chemical inertness of polytetrafluoroethylene (PTFE) and the precision of femtosecond laser microfabrication. The TOWC integrates a primary wedge channel with secondary micro-wedge arrays, enabling anti-gravity transport of low-surface-tension (LST) oils at velocities up to 57.9 mm s −1 in air and 15.8 mm s −1 underwater. The enhanced Laplace pressure and capillary rise at the corners, distinct from common single-wedge/grooved structures, are identified as the key driving forces governing LST liquid transport. Notably, the TOWC exhibits exceptional corrosion resistance, retaining over 95% of its transport efficiency after 30 days of immersion in saturated acetic acid and sodium hydroxide, far exceeding the durability of glass, PDMS, and aluminum counterparts. It also demonstrates remarkable abrasion resistance, maintaining stable performance over 200 cycles of sandy impact. Furthermore, the TOWC enables selective separation of immiscible oils with surface tension differences as small as 1 mN m −1 , long-distance transport along reconfigurable pathways, and efficient collection of floating oil droplets. This work offers a durable platform for advanced applications in chemical microreactors, targeted drug delivery, and lab-on-chip systems.
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