Clean and effective construction of SLIPS from porous polymer surface prepared by supercritical CO2 foaming technology

The gas-confined supercritical CO2 (scCO2) foaming technology is a clean method to prepare porous polymer surfaces but has never been applied to the construction of SLIPS due to the limitation of uneven and hard-controllable cell structure. In this paper, the surface of polystyrene (PS) is covered by a PS surface instead of the frequently-used rigid polymer films as a barrier, subsequently, both PS surfaces are foamed to prepare porous PS surfaces with uniform cell morphology and widely-adjustable cell size, which have active influences on the shear-resistant ability of SLIPS. Meanwhile, there is no solid waste generated in this process, and the production efficiency is at least doubled. The SLIPS with a cell-cell space of 0.07 μm and a mean cell diameter of 0.25 μm presents the optimal shear-resistant ability (CAH = 4.4° ± 0.8° after being sheared at 8500 rpm for 10 min). Consequently, this work proposes a clean, efficient, and facile path for preparing SLIPS with water-repellency, shear resistance, self-clean, and self-healing properties.