# Layered ZIFs Using a Surfactant as a Structure Directing Agent

## TL;DR

Researchers created a new layered ZIF material using a surfactant, which can be used to make gas-selective membranes.

## Contribution

A new layered ZIF material (ZIF-S) is synthesized using a surfactant as a structure-directing agent.

## Key findings

- ZIF-S has a tetragonal structure with specific unit cell parameters.
- ZIF-S can be converted into ZIF-8 or ZIF-67 when heated above 200 °C.
- ZIF-S is suitable for scalable gas-selective membrane fabrication.

## Abstract

Zeolitic imidazolate
frameworks (ZIFs) are three-dimensional (3D)
porous materials with only a few exceptions - ZIF-L, Zn2(benzimidazole)4, etc. Herein, we report the synthesis
of a new layered ZIF, which we call ZIF-S. We use a surfactant (sodium
dodecyl sulfate) as a structure-directing agent, analogous to the
concept used in the synthesis of zeolites. The layers contain individual
ZIF sheets intercalated by surfactants. Its ordered structure belongs
to the tetragonal lattice with the P4̅21
m space group. The unit cell parameters are a = b = 16.82 Å; c = 24.5 Å at room temperature. The layered material undergoes
topotactic condensation and forms its parent material (ZIF-8 or ZIF-67,
depending on the metal node) upon heating to or above 200 °C.
ZIF-S layers could be obtained with a large lateral size and a high
aspect ratio, which is ideal for the scalable preparation of gas-selective
membranes, thanks to the presence of pore apertures suitable for the
separation of small gas molecules. Fabrication of gas-selective membranes
from a simple coating of ZIF-S is demonstrated.