2, Angstrom Thin Film Technologies LLC, Albuquerque, New Mexico, United States
Selectively permeable membranes with high flux and high selectivity have important implications in many areas, such as water desalination, CO2 capture, H2 removal or purification, O2 separation, as well as selective ion transport for fuel cells and lithium batteries. Reduced membrane thickness and precisely constructed pore size/chemistry are the two keys for achieving combined high flux and high selectivity. In natural biological system, membranes can be as thin as 4 nm, and the pores/chemistries are elaborately constructed via molecular assembly, resulting in unbeatable performance compared to synthetic membranes. A manufacturing approach that ensures the structural and compositional precision is critical for high performance membranes. ALD is a layer-by-layer deposition method that builds up a thin layer with atomic precisions, and colloidal self-assembly is a method of building up materials in nm-level precisions. The combination of the two provides a new approach for membrane fabrication. Using this approach, hierarchically structured sub-50nm thick ultra-thin membranes with precisely defined pore size and pore surface chemistry have been successfully fabricated. Excellent performances in CO2 and oxygen separation have been achieved. The authors would like to acknowledge the support from DOE SBIR award number DE-SC0017178.