Asymmetric polysiloxane-based SiOC membranes produced via phase inversion tape casting process. (15th January 2021)

• Record Type: Journal Article
• Authors: Fontão, Natália Cristina; Wilhelm, Michaela; Rezwan, Kurosch
• Is Part Of: Materials & design. Volume 198(2021)
• Publication Date: 2021-01-15
• Subjects: Polysiloxane -- SiOC membrane -- Asymmetric membrane -- Phase inversion tape casting -- Microfiltration; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2020.109328
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: Asymmetric porous SiOC membranes with different pore characteristic and membrane morphology were produced for the first time by adapting the phase inversion tape casting technique to the polymer-derived ceramic route. Polymethyl siloxane (MK) was used as a ceramic precursor. The produced tapes were pyrolyzed under N2 atmosphere. The structure and surface characteristics were tailored by changing the pyrolysis temperatures (600 and 1000 °C), polyvinylpyrrolidone and solid loading. Scanning electron microscopy analysis revealed the asymmetric morphology composed by a thin skin-layer (average pore size <2 μm) and a sponge-like support. The differences in membranes porosity (33–47%) and overall pore size distribution (1–10 μm) can be controlled by adjusting the slurry composition. The incorporation of particles improved the slurry processability, enhanced the mechanical flexural resistance of the membrane (20–48 MPa), and reduced the average pore size. Higher mechanical strengths and enhanced hydrophilic character are associated with higher pyrolysis temperatures (ceramization process). The water permeation of membranes pyrolyzed at 1000 °C were assessed in a dead-end configuration device under different pressures (1–3 bar). The obtained water permeation fluxes (6–55 m 3 /m 2 ·h, at 3 bar) indicates the advantages of the asymmetric structure which minimizes mass transport limitations. Graphical abstract: Unlabelled Image Highlights: Porous SiOC membranes were produced by adapting the phase inversion technique to the polymer-derived ceramic route. The open porosity (33–47%) and overall pore size distribution (1–10 μm) was tailored according to the slurry composition. The increase in pyrolysis temperature from 600 °C to 1000 °C enhanced the hydrophilic character of the membranes. Higher pyrolysis temperature led to improved mechanical resistance (6–13 to 20–48 MPa). Asymmetric membranes presented a 10-fold improved permeation performance when compared to their symmetric counterpart.