title: Nano-TiO2/polyurethane composites for antibacterial and self-cleaning coatings.
abstract: Grafting from polymerization was used to synthesize nano-titania/polyurethane (nTiO(2)/polyurethane) composite coatings, where nTiO(2) was chemically attached to the backbone of the polyurethane polymer matrix with a bifunctional monomer, 2,2-bis(hydroxymethyl) propionic acid (DMPA). This bifunctional monomer can coordinate to nTiO(2) through an available -COOH group, with two available hydroxyl groups that can react with diisocyanate terminated pre-polyurethane through step-growth polymerization. The coordination reaction was monitored by FTIR and TGA, with the coordination reaction found to follow first order kinetics. After step-growth polymerization, the polyurethane nanocomposites were found to be stable on standing with excellent distribution of Ti in the polymer matrix without any significant agglomeration compared to simple physical mixtures of nTiO(2) in the polyurethane coatings. The functionalized nTiO(2)-polyurethane composite coatings showed excellent antibacterial activity against gram-negative bacteria Escherichia coli; 99% of E. coli were killed within less than one hour under solar irradiation. Self-cleaning was also demonstrated using stearic acid as a model for 'dirt'.
authors.affiliation: Department of Chemical and Biochemical Engineering, University of Western Ontario, London, ON, N6A 5B9, Canada. pcharpentier@eng.uwo.ca
authors.forename: P A
authors.initials: PA
authors.lastname: Charpentier
authors.forename: K
authors.initials: K
authors.lastname: Burgess
authors.forename: L
authors.initials: L
authors.lastname: Wang
authors.forename: R R
authors.initials: RR
authors.lastname: Chowdhury
authors.forename: A F
authors.initials: AF
authors.lastname: Lotus
authors.forename: G
authors.initials: G
authors.lastname: Moula
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D020099:Coated Materials, Biocompatible / Q000494:pharmacology*; D004655:Emulsions; D004926:Escherichia coli / Q000187:drug effects; D006880:Hydroxy Acids / Q000737:chemistry; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D011140:Polyurethanes / Q000737:chemistry*; D011422:Propionates / Q000737:chemistry; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D013229:Stearic Acids / Q000737:chemistry; D013818:Thermogravimetry; D014025:Titanium / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D020099:Coated Materials, Biocompatible; D004655:Emulsions; D006880:Hydroxy Acids; D011140:Polyurethanes; D011422:Propionates; D013229:Stearic Acids; C009495:titanium dioxide; C031183:stearic acid; C110034:2,2-bis(hydroxymethyl)-propionic acid; D014025:Titanium