Nano-Interlayers
Fabricated via Interfacial Azo-Coupling
Polymerization: Effect of Pore Properties of Interlayers on Overall
Performance of Thin-Film Composite for Nanofiltration
The supporting layer of nanofiltration
membranes is critical to
the overall nanofiltration performance. However, conventional supports
lack efficient surface porosity, which leads to the limited utilization
rate of the polyamide (PA) layer. Herein a double-skin-layer nanofiltration
membrane with porous organic polymer nanointerlayers prepared via
a two-step interfacial polymerization technique is presented to investigate
the effect of the interlayers’ pore properties on the performance
of the thin-film composite. Nanometer interlayers with different pore
sizes are fabricated via interfacial azo-coupling polymerization.
The pore properties of the nanointerlayer extremely influence the
permeance, where a suitable pore size of 4.22 nm promotes pure water
permeance of up to 32.2 L m–2 h–1 bar–1, which is ∼3.8-fold greater than
the membrane without an interlayer. However, an interlayer with 0.54
nm pores limits the performance (4.7 L m–2 h–1 bar–1), which is even lower than
the unmodified membrane (7.5 L m–2 h–1 bar–1), because of the narrow pores and confined
transport mode. However, the confined diffusion rate of amino monomers
from the support to interface leads to a thinner PA layer of ∼45
nm and results in high flux. This work provides a facial route for
the fabrication of interlayers and facilitate the design of high-performance
membrane materials with interlayers.