Thermally induced transformation of ZIF-8 to ZnF2 in CNT/PVDF composite membranes for tunable porosity and gas transport
Year: 2026
Type: article
Abstract: Gas separation membranes offer an energy-efficient alternative to conventional separation technologies, yet achieving high permeability and selectivity simultaneously remains a challenge. Here, we fabricate thin composite membranes composed of carbon nanotubes (CNTs), polyvinylidene fluoride (PVDF), and zeolitic imidazolate framework-8 (ZIF-8), and investigate the effect of heat treatment on their structural and transport properties. Thermal analysis, XRD, and XPS reveal that PVDF decomposition releases HF, which reacts with ZIF-8 to form ZnF2, inducing pore formation and altering the polymer structure. Gas permeation measurements show that ZIF-8 incorporation enhances overall permeability, while heat treatment drives a transition in transport mechanism from solution-diffusion to a mixed regime of molecular sieving and Knudsen diffusion. For example, the H2 permeability of CNT/PVDF membrane increased by more than an order of magnitude, from 0.41 to 25.4 Barrer for CPZ73(330) while also increasing in selectivity against larger molecules. Unlike conventional mixed-matrix membranes where fillers remain inert, ZIF-8 acts as a reactive partner that tailors the polymer microstructure. This work demonstrates a scalable, single-step approach for generating tunable gas transport pathways and offers a general framework for thermally reactive polymer–MOF membrane design in industrial separations.
Authors: Chris Yeajoon Bon, Gwanwon Lee, Wonyeong Kim, Sungho Lee, Sejoon Park
Institution: Korea Institute of Science and Technology
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,060
Awards: G1752193170, G2661603285, G37908169
OpenAlex ID: W7125498906