Sewage Water-Repellent PDMS and Magnetic Silicone Composites: Lab to Commercialization

Abstract

Liquid-repellent surfaces are beneficial for improving corrosion resistance, anti-biofouling, anti-icing, and reducing material sticking in food, beverages, cosmetics, and medical industries. However, limited research data are available on fabricating sewage water-repellent surfaces, which should repel suspended organic/inorganic and biological matter in addition to water. Herein, we unveil the sewage water repellency and superhydrophobicity of magnetic silicone composites and poly-(dimethylsiloxane) (PDMS). Hexagonally arranged microconical pillars (Wenzel roughness of 1.2−2.4) were printed via hot embossing and replica molding methodologies. High static contact angles of ∼160°, low contact angle hystereses of ∼5°, and low roll-off angles of ∼5°were achieved. At least 30 textured silicone composites were fabricated by successively hot embossing from a single custom-made and durable commercializable Ni−steel mold. All of them demonstrated excellent replication efficiency and retained superhydrophobicity and sewage water repellency as a function of embossing cycles. Furthermore, sewage water and deionized water droplets bounced off the silicone composite surface for a Weber number of up to 149, revealing a robust Cassie configuration. Furthermore, textured surfaces retained under-sewage water phobicity for up to 24 h, when submerged at 3 cm depth (0.3 kPa gauge pressure), wherein coated and untextured surfaces have failed just within 15 min, i.e., covered by a liquid film or sticky droplets. Also, textured surfaces inhibited the growth of the Escherichia coli bacterium, while a huge biofilm was observed on the untextured region. Briefly, this is the first demonstration of a one-step, upscalable, and facile hot embossing methodology to manufacture sewage water-repellent silicone composite and PDMS surfaces.

Pressure-Responsive Self-Lubricating Ice-Phobic Organogel with High Mechanical Strength from Fluorinated Polynorbornene Networks

“…Traditionally, hydrophobic surfaces of anti-icing materials, which were prepared by simply changing the chemical compositions of the materials, have some defects to restrict their applications . Moreover, the superhydrophobic surface developed later also did not show long-term stable anti-icing performance, owing to the easy damage of the micro-nanostructure on the surface. − Subsequently, slippery liquid-infused porous surfaces (SLIPS) were investigated, which can reduce the adhesion between the ice and the surface by adding lubricants such as paraffin and fluorinated oil into the porous surface. − However, gravity, flowing water, deicing, and other factors could lead to loss of lubricating oil, thereby deteriorating the anti-icing performance. − …”