Efficient separation of biphasic mixtures, especially oil/water mixtures, is critical to many applications, including wastewater treatment and chemical recovery. In search of smart materials for complex separations, such as on-demand operations, Kening Sun and co-workers, Harbin Institute of Technology, Heilongjiang, China, have developed a copper mesh film that can switch between different states of wettability in response to pH. The mesh is funtionalized with Cu(OH)2 nanorods and then coated with thiols. With appropriate pore sizes, the resulting films turn from superhydrophobic to superhydrophilic when pH changes from 7 to 12. This allows water, but not oil, to go through.
The researchers have demonstrated the convenient pH-controlled separation of both immiscible and emulsive water/oil systems using this new type of mesh. In addition, when combined with other techniques, the switchable copper mesh may be used in microfluidic devices and controllable filtration, among others.
- pH-Controllable On-Demand Oil/Water Separation on the Switchable Superhydrophobic/Superhydrophilic and Underwater Low-Adhesive Superoleophobic Copper Mesh Film,
Zhongjun Cheng, Jingwen Wang, Hua Lai, Ying Du, Rui Hou, Chong Li, Naiqing Zhang, Kening Sun,