The researchers used cylindrical glass vials of different sizes (6.35, 7.35, and 9.35 mm inner radius) and surface treatments (hydrophilic, untreated, and hydrophobic). They added methylene blue dye ...

Hydrophobic particles have the property of repelling water ... that the liquid robot can pass between small pillars like water seeping through or swallow glass beads and seamlessly merge with other ...