Multibioinspired slippery surfaces with wettable bump arrays for droplets pumping

Abstract

Droplet manipulation is playing an important role in various fields, including scientific research, industrial production, and daily life. Here, inspired by the microstructures and functions of Namib desert beetles, Nepenthes pitcher plants, and emergent aquatic plants, we present a multibioinspired slippery surface for droplet manipulation by employing combined strategies of bottom-up colloidal self-assembly, top-down photolithography, and microstructured mold replication. The resultant multilayered hierarchical wettability surface consists of hollow hydrogel bump arrays and a lubricant-infused inverse opal film as the substrate. Based on capillary force, together with slippery properties of the substrate and wettability of the bump arrays, water droplets from all directions can be attracted to the bumps and be collected through hollow channels to a reservoir. Independent of extra energy input, droplet condensation, or coalescence, these surfaces have shown ideal droplet pumping and water collection efficiency. In particular, these slippery surfaces also exhibit remarkable features including versatility, generalization, and recyclability in practical use such as small droplet collection, which make them promising candidates for a wide range of applications.

Biomimicking properties of cellulose nanofiber under ethanol/water mixture

“…Interestingly, the oil rejection works not only underwater but also in air. The in-air oil rejection property is similar to that of a Nepenthes pitcher surface 35 . This indicates that CNF is mimicking not only fish skin but also Nepenthes pitcher.…”

Directional liquid dynamics of interfaces with superwettability

“…For example, desert beetles have patterns of hydrophobic troughs and hydrophilic bumps on their backs (22), spider silks have intrinsic hydrophilic wet-rebuilt periodic spindle knots and joints (9), cactus stems have conical spines to transport water droplets consistently in a specific direction (10), and Sarracenia trichomes have a unique hierarchical microchannel organization (26). Learning from nature, a large number of bionic liquid transport and collection devices have been developed and fabricated (27,(84)(85)(86). For example, Park et al (84) proposed a combination of strategies that were learned from three distinct biological examples-Namib desert beetles, cacti, and Nepenthes pitcher plants-to integrate the growth and transport of water droplets.…”

Chinese herb microneedle patch for wound healing

“…Microneedle (MN) patch has been proposed as a versatile technique and gained a great deal of remarkable achievements in the field of wound healing, as well as disease therapy, biosensing, dermal vaccination, and so on [ [12] , [13] , [14] , [15] , [16] , [17] , [18] ]. Because of their well-designed microstructures and superior loading capacity compared to those regular drug delivery carriers, MN can effectively realize the load and delivery of the favored active drugs [ [19] , [20] , [21] , [22] , [23] ]. However, the MN widely utilized nowadays is usually fabricated by synthetic polymer materials obtained through complicated chemical synthesis involving environmentally unfriendly organic reagents and harsh experimental treatments, increasing the risk of side effects [ [24] , [25] , [26] , [27] , [28] ].…”