Photonic liquid crystals of graphene oxide for fast membrane nanofiltration
Alice C. Lin,
Fangyou Xie,
Liam J. McCarthy,
David R. Rodgers,
Kyle G. Hoff,
Maximilian R. von Welczeck,
Sixin Zhai,
Andrea C. Saw,
Gregory E. Scott,
Shanju Zhang
Affiliations
Alice C. Lin
Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, California 93407, United States
Fangyou Xie
Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, California 93407, United States
Liam J. McCarthy
Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, California 93407, United States
David R. Rodgers
Department of Physics, California Polytechnic State University, San Luis Obispo, California 93407, United States
Kyle G. Hoff
Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, California 93407, United States
Maximilian R. von Welczeck
Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, California 93407, United States
Sixin Zhai
Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, California 93407, United States
Andrea C. Saw
Department of Materials Engineering, California Polytechnic State University, San Luis Obispo, California 93407, United States
Gregory E. Scott
Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, California 93407, United States
Shanju Zhang
Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, California 93407, United States; Corresponding author.
The photonic liquid crystalline (LC) dispersion of graphene oxide (GO) is prepared using centrifugation-induced size-fractionization. Under gravity, a series of successive centrifugations enable large GO sheets to sediment and fractionize into a narrowed size distribution. The resulting large GO sheets display large-area monodomain structures with uniform orientation, forming a photonic LC phase. The single lyotropic LC phase forms at the concentration > 0.34 wt% and structural coloring occurs at the concentration > 0.59 wt%. The structural color with different wavelength is tuned with various concentrations (0.59–0.92 wt%). GO membranes are supported on porous poly(ether sulphone) membranes from photonic LC dispersions by a vacuum-spin method. The photonic GO membrane demonstrates dramatic enhancement of water permeance (169.3 Lm−2 hr−1 bar−1), which is 12 times faster than the control GO membrane (13.2 Lm−2 hr−1 bar−1). The ion rejection of the photonic GO membrane (45–60%) is also significantly improved, as compared to the control GO membrane (30–48%). Organic dye rejection testing shows that the photonic GO membrane remains as high molecular rejection (> 90%) as the control GO membrane. This work may provide a new way to fabricate ordered GO membranes for fast nanofiltration.
