Hydrophobicity control by a supercritical drying technique in a sol–gel process with hybrid materials

• Sol–gel route is combined with polymerization without using modifier.
• Supercritical drying control is the key to obtain super-hydrophobic surfaces.
• The whole fabrication is technologically controllable and with low costs.
• The production rate is higher than 90%.
• The method provides a cost-effective way for industry applications.

We successfully synthesized one type of cheap super-hydrophobic hybrid porous materials in a sol–gel process. In this route, hydrophilic polymers and TEOS-base sol are used as precursors, the ultraviolet ray-initiated polymerization and supercritical fluid drying techniques are combined together to fulfill this task. All fabricated samples exhibit lotus-leaf-like surface structures with super-hydrophobicity. The underlying mechanisms are carefully investigated using a field-emission scanning electron microscopy (FESEM) and an X-ray photoelectron spectroscopy (XPS). We found that a well-controlled drying process is crucial to the formation of such super-hydrophobic surfaces. As high as 90% production rate is obtained in our route and thus, it might provide a cost-effective way to produce super-hydrophobic hybrid materials for industry applications.

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