Stretch-Enhanced Anisotropic Wetting on Transparent Elastomer Film for Controlled Liquid Transport

Abstract

Direction-controlled wetting surfaces, special for lubricating oil infused anisotropic surfaces, have attracted great research interest in directional liquid collection, expelling, transfer, and separation. Nonetheless, there are still existing difficulties in achieving directional and continuous liquid transport. Herein, we present a strategy to achieve directional liquid transport on transparent lubricating oil infused elastomer film with V-shaped prisms microarray (VPM). The results reveal that the water wetting direction in the parallel and staggered arrangement of the VPM structure surface with lubricating oil infusion is the opposite, which is completely different from the wetting direction on the usual VPM surface in air. Moreover, asymmetric stretching can enhance or weaken the directional water wetting tendency on the lubricating oil infused VPM elastomer film and even can reverse the droplet wetting direction. In a closed moist environment, tiny droplets gradually coalesce and then slip away from the lubricating oil infused VPM surface to keep the surface transparent, due to the cooperation of imbalanced Laplace pressure, resulting from the anisotropic geometric structures, varying VPMs spacing, and gravity. Thus, this work provides a paradigm to design and fabricate a type of surface engineering material in the application fields of directional expelling, liquid collection, anti-biofouling, anti-icing, drag reduction, anticorrosion, etc.

Droplet Bouncing: Fundamentals, Regulations, and Applications

“…Surface Wettability Gradient: Making millimeter-sized droplet move toward the designed direction is desired in wide liquid-manipulation-related [125][126][127][128][129][130][131][132][133] applications like liquid collection, [134][135][136][137][138][139][140][141][142][143][144][145][146][147][148][149][150] printing, [151] hydropower utilization optimization [152,153] or microfluidics. [154,155] By designing a nonwetting solid surface with a wettability gradient, vertical momentum of impacting droplet can be transferred to horizontal momentum with the designed direction.…”

Anisotropic Hemiwicking Behavior on Laser Structured Prismatic Microgrooves

“…The control of macroscopic wicking dynamics, particularly the tuning of wicking speed in different directions by either patterning surface free energies or designing geometrically anisotropic structures, is of great significance for practical applications, including thermal management, controllable liquid transport, intelligent inkjet printing, brazing, and soldering. − For instance, such anisotropic wicking structure designs are of particular interest to the burgeoning developed thermal management community due to the need to cool heterogeneous materials with specific heat load configurations. , Superhydrophilic surfaces with high anisotropic wicking qualities can be utilized to create desired flow paths that can direct the continuous liquid to specific hot- or cold-spot regions of interest. Also, anisotropic wicking qualities tailored flow fields are efficient methods for directional liquid collection, expelling, transfer, and separation. − Bal et al fabricated asymmetric half-conical micropillars utilizing two-photon polymerization to explore the upward anisotropic hemiwicking behavior experimentally and theoretically. Li et al presented a strategy to achieve directional and continuous water transportability by fabricating a lubricating oil-infused V-shaped prisms microarray elastomer film with excellent anisotropic wetting performance.…”

“…Also, anisotropic wicking qualities tailored flow fields are efficient methods for directional liquid collection, expelling, transfer, and separation. − Bal et al fabricated asymmetric half-conical micropillars utilizing two-photon polymerization to explore the upward anisotropic hemiwicking behavior experimentally and theoretically. Li et al presented a strategy to achieve directional and continuous water transportability by fabricating a lubricating oil-infused V-shaped prisms microarray elastomer film with excellent anisotropic wetting performance. Hitherto, extensive effort has been paid to fabricate various anisotropic wicking structures and boost the unidirectional liquid spreading, while only a little work has attempted to investigate and model the two- dimensional anisotropic wicking behavior, much less to attempt to tailor the wicking velocities in different directions.…”

Gradient monolayered porous membrane for liquid manipulation: from fabrication to application

“…33,[52][53][54] In the former case, the monolayered porous membranes are formed by chemical or physical processing. [55][56][57] The asymmetric decoration surface is achieved by post-modication, which causes different wettability, morphology or composition. [58][59][60][61] This section focuses on the fabrication of several commonly used monolayered porous membranes, which lays a foundation for the design of new porous structures.…”