Reversible Switching of Water-Droplet Mobility on a Superhydrophobic Surface Based on a Phase Transition of a Side-Chain Liquid-Crystal Polymer

摘要

Superhydrophobic surfaces with different dynamic wettabilities, such as water repellent or water adhesive, have attracted increasing interest recently. The lotus leaf, with ultrahigh water contact angle (CA) and low sliding angle (SA), is widely known as a model superhydrophobic surface because of its self-cleaning property. Although superhydrophobic surfaces with high SA cannot be self-cleaning, they have many other potential applications, such as in the field of microfiuidic control systems. Superhydrophobic surfaces that can "pin" liquid droplets have been demonstrated for no-loss microdroplet transfer or trance-liquid reactors. It is known that super-hydrophobicity is effective for obtaining a small liquid interfacial contact area (ICA), at least for water-based liquids, which significantly reduces the mass loss in microdroplet transfer. To construct more dense and complicated microfiuidic devices, the integration of superhydrophobicity and reversible switching of water mobility would be desirable.