Membranes with selective superwettability for oil/water separation have received significant attention during the past decades. Hierarchical structures and surface roughness are believed to improve the oil repellency and the stability of Cassie-Baxter state. Diatoms, unicellular photosynthetic algae, possess sophisticated skeletal shells (called frustules) which are made of hydrated silica. Motivated by the hierarchical micro- and nanoscale features of diatom, we fabricate a hierarchical diatomite membrane which consists of aligned micro-sized channels by the freeze casting process. The fine nano-porous structures of frustules are well preserved after the post sintering process. The bioinspired diatomite membrane performs both underwater superoleophobicity and superhydrophobicity under various oils. Additionally, we demonstrate the highly efficient oil/water separation capabililty of the membranes in various harsh environments. The water flux can be further adjusted by tuning the cooling rates. The eco-friendly and robust bioinspired membranes produced by the simple, cost-effective freeze casting method can be potentially applied for large scale and efficient oil/water separation.

Robust stalagmite-like self-cleaning surfaces with good transparency and flexibility are developed by plasma-assisted nanofabrication and silanization under ambient conditions.

No abstract

In this paper, a dual membrane restrictor design was proposed to improve the stiffness performance of the compensated hydrostatic bearing. Theoretical models for the proposed dual membrane restrictors were derived. Analysis of these models showed that a high stiffness region could be achieved at the desired loading region through the proper selection of the design parameters. A series of simulations were conducted to study the variations in the design parameters on the stiffness and clearance variations. It was found that the dimensionless membrane stiffness in the inlet restrictor, Kmi*, was the most dominant parameter for the performance of the compensated bearing system. The main advantages of the proposed dual membrane restrictor are the increase in flexibility by providing high stiffness at the desired loading region; and improving the stiffness performance of the bearing system especially at the desired loading region.

Hierarchically stalagmite-like tungsten-oxide protrusions on stainless steel mesh exhibited superior selective superwettability toward low surface tension oils under harsh environments.