Abrasion-resistant superhydrophilic objects with anisotropic water transport capacities prepared by a selective laser sintering 3D printing strategy

Liquid directional manipulation has been widely used in the fields of microfluidic, microreactor, liquid separation and collection, sewage treatment. Most studies based on the construction of gradient structures on the substrate surface realized liquid directional transportation, but their fragile surfaces are vulnerable to external forces and can only transport thin water film according to the array thickness. Here, we report that abrasion-resistant superhydrophilic objects with anisotropic water transport capacities can be one-step constructed by selective laser sintering (SLS) the composites of hydrophilic glass beads (GBs) and thermoplastic phenol–formaldehyde resin (PF) grains. The long interlayer micro-slits between the adjacent printing layers cooperated with the inserted hydrophilic GBs formed long capillary channels, resulting in anisotropic water transport abilities on different printing surfaces. In addition, the abrasion-resistant ability endowed superhydrophilic mechanical stability. Furthermore, water could climb about ∼26 cm along the horizontal printed sample, showing excellent anti-gravity water transport ability. Finally, we demonstrated that the printed evaporators with diverse salt-resistant structures not only maintain long-term salt resistance, but also possess high evaporation efficiency. The superhydrophilic materials proposed in this study will lead the design and preparation of liquid directional transport materials and provide advanced inspiration for 3D printing functional materials.