Antimicrobial Properties and Thermal Stability of Polycarbonate Modified with 1-Alkyl-3-methylimidazolium Tetrafluoroborate Ionic Liquids Sergiy Rogalsky, 1 Kateryna Fatyeyeva, 2,3,4 Lyudmila Lyoshina, 1 Oksana Tarasyuk, 1 Olga Bulko, 1 Sofiia Lobok 5 1 Institute of Bioorganic Chemistry and Petrochemistry, National Academy of Science of Ukraine, 50, Kharkivske schose, Kyiv 02160, Ukraine 2 Normandie Univ, France 3 Universit e de Rouen, PBS, Bd. Maurice de Broglie, 76821 Mont Saint Aignan cedex, France 4 CNRS, UMR 6270, FR 3038, Bd. Maurice de Broglie, 76821 Mont Saint Aignan cedex, France 5 Institute of Macromolecular Chemistry, National Academy of Science of Ukraine, 48, Kharkivske schose, Kyiv 02160, Ukraine Correspondence to: S. Rogalsky (E - mail: rogalsky@bpci.kiev.ua) ABSTRACT: Four water immiscible ionic liquids (ILs): 1-hexyl-3-methylimidazolium tetrafluoroborate, 1-heptyl-3-methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium tetrafluoroborate and 1-dodecyl-3-methylimidazolium tetrafluoroborate have been synthesized. Polycarbonate (PC) films containing ILs were prepared by solvent casting from methylene chloride solutions. Scanning electron microscopy measurements showed the high homogeneity of PC/IL films with the IL content up to 4 wt %. The tendency to IL aggregation was observed for polymeric films with higher IL content (5%). PC/IL composites were found to have the reduced ther- mal decomposition temperature under both an air and a nitrogen atmosphere in comparison with the neat PC. The effect of IL con- tent on the antimicrobial activity of PC films against Escherichia coli bacteria was studied. Pronounced antimicrobial efficacy was revealed for PC/IL films for all studied ILs starting from 3 wt % of IL. V C 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40050. KEYWORDS: polycarbonates; films; ionic liquids; thermogravimetric analysis; degradation Received 20 June 2013; accepted 9 October 2013 DOI: 10.1002/app.40050 INTRODUCTION Polycarbonate (PC) is one of the most widely used engineering polymers due to its unusual combination of optical clarity, heat resistance, high impact strength, and dimensional stability over wide thermal range. 1,2 PC had been popular for the production of electronic devices housing and instrumental panels, optical lenses, transparent building constructions, decorative laminates, protective shields, packaging films, domestic appliance etc. 1,2 Low water absorption, ease of sterilization and biocompatibility of PC have led to its use in a wide range of medical equipment, including critical medical devices. 1–3 It is well known that the plastic material surfaces can be quickly contaminated with pathogens like bacteria, mildew and fungi when contacted with humid environment or when operated in climate controlled conditions. The microbial growth on poly- meric surfaces leads to the odours development, staining, as well as deterioration of their functionality. The microbial trans- fer is typical for articles handled by many people, such as mobile phones housing, touch-screen displays, computer key- board etc. The prevention of biofilm formation on the internal medical devices is also of great importance since it can initiate a degradation process of the material, as well as cause infections and health related problems. 4 There is an increasing interest in the development of PC having antimicrobial properties for its use in the field of health protec- tion, in consumer goods production, food industry etc. To obtain antimicrobial properties, polymers are usually com- pounded with organic or inorganic biocides. 4–7 However, the use of organic biocides as additives for PC is significantly lim- ited due to their insufficient thermal stability in the temperature range used for PC processing (300–320  C). Today silver or silver-ion containing nanoparticles are consid- ered the most efficient antimicrobial additives for various ther- moplastic polymers including PC because of the broad spectrum of biocide effect, as well as excellent thermal stability and high migration resistance out of polymer matrix. 7,8 The V C 2013 Wiley Periodicals, Inc. WWW.MATERIALSVIEWS.COM J. APPL. POLYM. SCI. 2014, DOI: 10.1002/APP.40050 40050 (1 of 7)