Preparation of large, ultra-flexible and free-standing nanomembranes of metal oxide–polymer composite and their gas permeation properties

Anteneh Mersha,Roman Selyanchyn,Shigenori Fujikawa

doi:10.1093/ce/zkx006

Abstract

Abstract In this work, fabrication of free-standing nanomembranes of metal oxide (MOx) and polymers by simple spin-coating method is discussed. First, double-layer nanomembranes containing MOx and epoxy resin of polyethyleneimine and poly[(o-cresyl glycidyl ether)-co-formaldehyde] were prepared. Free-standing nanomembranes were successfully prepared, but defects formed in the metal oxide nanolayer during sharp bending of the nanomembrane. To overcome fragility of MOx nanolayer, poly(vinyl alcohol) nanolayers were introduced between MOx nanolayers by layer-by-layer (LbL) assembly process. The LbL nanomembrane was also free-standing and was highly flexible during macroscopic membrane manipulations. Even after transfer of the LbL nanomembrane onto a porous support, it did not have apparent cracks, confirmed by scanning electron microscopy (SEM). The LbL nanomembrane sustained low gas permeance, confirming the absence of significant defects, although it shows excellent flexibility. We believe that the presented LbL nanomembrane could be a platform useful for the design of molecular nanochannels, which is the next challenge for efficient gas separation.

Highlights

Membranes have been explored as an efficient alternative for gas separation over other CO2 capture processes, such as liquid absorption and solid adsorption, due to their lower operational energy cost [1, 2]
We believe that the presented LbL nanomembrane could be a platform useful for the design of molecular nanochannels, which is the challenge for efficient gas separation
We have attempted to form the stable thin metal oxide layers deposited on well-established polymeric nanomembrane [27]

Summary

Introduction

Membranes have been explored as an efficient alternative for gas separation over other CO2 capture processes, such as liquid absorption and solid adsorption, due to their lower operational energy cost [1, 2]. Organic polymeric membranes have been widely investigated to take advantage of their flexibility and solution processability [3]. Such materials are prone to gas permeability–selectivity trade-off behavior [4, 5]. Membranes with high gas flux are strongly sought after the gas selectivity by the current state-of-the-art membranes is satisfactory for practical use. Thinning is one of the promising approaches to improve the gas permeance of separation membranes.

Methods

Results

Discussion

Conclusion