File Name : fig.s1.tiff

Caption : fig.s1 schematic illustrations (left) and corresponding optical microscope images (right) of the fabrication process for patterned structures on pdms substrates. (a) laser cutting of chevron-ratchet geometry patterns into a double-sided pet tape using a femtosecond laser system. the inset shows the resulting pattern features on the tape. (b) laminating the patterned tape onto a thin pdms substrate (~500 μm thickness). optical micrographs show the transferred pattern on the pdms surface prior to treatment. (c) oxygen plasma treatment of the assembled substrates with varying exposure durations, followed by tape removal. the resulting surface exhibits an invisible boundary between hydrophilic (plasma-exposed) and hydrophobic (tape-protected) regions, forming localized wettability contrast. scale bar: 100 μm.

File Name : fig.s2.tiff

Caption : fig. s2. visualization of surface cracking on pdms substrates under y-axis stretching. a ~500 nm-thick gold layer was sputter-deposited onto the pdms surface to facilitate crack observation. the substrate was stretched along the y-axis using a custom mechanical platform while monitoring surface deformation via optical microscopy. as the elongation increased, wider and more pronounced cracks developed, oriented perpendicular to the stretching direction. scale bar: 100 μm.