Covalent and Selective Grafting of Polyethylene Glycol Brushes at the Surface of ZIF-8 for the Processing of Membranes for Pervaporation

Marvin Benzaqui (1, 2) , Rocio Semino (3) , Florent Carn (4) , Sérgio Rodrigues Tavares (3) , Nicolas F Menguy (5) , Mónica Giménez-Marqués (2, 1) , Elena Bellido (1) , Patricia Horcajada (1, 6) , Thomas Berthelot (7, 8) , Anna Kuzminova (9) , Maria Dmitrenko (9) , Anastasia Penkova (9) , Denis Roizard (10) , Christian Serre (1, 2) , Guillaume Maurin (3) , Nathalie Steunou (1)

1 ILV - Institut Lavoisier de Versailles
2 IMAP - Institut des Matériaux Poreux de Paris
3 ICGM - Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier
4 MSC - Matière et Systèmes Complexes
5 IMPMC - Institut de minéralogie, de physique des matériaux et de cosmochimie
6 Instituto IMDEA Energía
7 LICSEN - Laboratoire Innovation en Chimie des Surfaces et NanoSciences
8 SPCSI - Service de Physique et de Chimie des Surfaces et Interfaces
9 SPBU - Saint Petersburg University
10 LRGP - Laboratoire Réactions et Génie des Procédés

The so-called Graftfast reaction in water and at room temperature (RT) was applied to graft polyethylene glycol (PEG) at the surface of the microporous zeolitic imidazolate framework ZIF-8 nanoparticles (NPs) using acrylPEG of different chain lengths (480 Da and 5 kDa). In comparison to non-modified ZIF-8 NPs, both chemical and colloidal stabilities of PEGylated ZIF-8 NPs are significantly enhanced in water. A series of colloidal complex fluids by mixing PEG grafted ZIF-8 (i. e. PEG-g-ZIF-8) NPs with different amounts of polyvinylalcohol (PVA) was prepared and characterized by advanced characterization tools such as dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS) thereby showing their long-term colloidal stability. Finally, dense and supported mixed matrix membranes were cast from PEG-g-ZIF-8/PVA solutions and have shown high performance in isopropanol (IPA) dehydration by pervaporation. The permeation flux of the supported MMM (i. e. 0.091 kg/(m$^2$h) is eleven times higher than that of the pure PVA membrane and these MMMs present a high separation factor (i. e. 7326). These transport properties are presumably due to the molecular sieving effects induced by ZIF-8 and the good interfacial properties of the membrane. The computational exploration of the ZIF-8/PVA and PEG/PVA interfaces provides a microscopic scale explanation for the enhanced compatibility of PVA with the PEGylated MOF when compared to that for the composite based on the bare ZIF-8 as a filler.

Keywords: Membranes; MOFs; Pervaporation; Poly(vinyl alcohol); Surface modification

Domains: Material chemistry

Marvin Benzaqui, Rocio Semino, Florent Carn, Sérgio Rodrigues Tavares, Nicolas F Menguy, et al.. Covalent and Selective Grafting of Polyethylene Glycol Brushes at the Surface of ZIF-8 for the Processing of Membranes for Pervaporation. ACS Sustainable Chemistry & Engineering, 2019, 7, pp.6629-6639. ⟨10.1021/acssuschemeng.8b05587⟩. ⟨cea-02072200⟩