Catalyst loaded porous membranes for environmental applications: Smart Membranes
2007 (English)Student thesis
This project involves the fabrication and testing of microporous, polymer membranes designed to remove minute amounts of toxic air pollutants such as formaldehyde from air streams. The hypothesis to be tested is that active, the silver contained within the porous polymer membranes results in high formaldehyde retention.
Monolayers consist of different sizes of sPS particles are assembled first on the silicon wafers by spin coating method and convective assembly method, respectively. Then each kind of monolayer with one dimension of sPS particles is deposited with a nanometer scaled silver thin film with a bench top metal evaporator. The porous membranes are produced by assembly of close-packed colloidal crystals of silver capped polystyrene template particles and subsequent infiltration with polyurethane prepolymer. The prepolymer is cured by UV exposure. The sPS particles are removed from the particle polymer membrane by treatment with organic solvents resulting in the formation of inverse opal structures. Silver does not dissolve in the organic solvents and cannot leave the pores due to the small size of connecting holes in an inverse opal. All the monolayers, cylindrical colloidal crystals and microcapillaries after infiltration of polyurethane had been characterized by optical microscope, and the porous membranes had been characterized by SEM.
The application of porous membranes with silver caps is to absorb formaldehyde in the air, while in fact the silver caps are oxidized and become Ag2O, which will initiate a gas-phase/solid reaction with formaldehyde. In the future, TiO2 will be applied together with Ag2O, since TiO2 is another good absorbent for formaldehyde
Place, publisher, year, edition, pages
Stockholm: KTH , 2007. , 47 p.
Trita-MAT, ISSN 1401-2286
polystyrene, monolayer, silver caps, microcapillary, porous membrane
IdentifiersURN: urn:nbn:se:kth:diva-4619OAI: oai:DiVA.org:kth-4619DiVA: diva2:13104