Polysiloxanes With Quaternary Ammonium Salt Biocidal Functions and Their Behavior When Incorporated Into a Silicone Elastomer Network Witold Fortuniak • Urszula Mizerska • Julian Chojnowski • Teresa Basinska • Stanislaw Slomkowski • Mohamed M. Chehimi • Agnieszka Konopacka • Katarzyna Turecka • Wladyslaw Werel Received: 28 February 2011 / Accepted: 1 April 2011 / Published online: 17 April 2011 Ó Springer Science+Business Media, LLC 2011 Abstract Polysiloxanes of various structures having bio- cidal quaternary ammonium salt (QAS) groups pendant to the polymer chain were prepared. Their antibacterial activ- ities were compared in aqueous solution. Selected poly- siloxanes were linear polydimethylsiloxanes having 20% siloxane units substituted at silicon by 3(dimethyl-n-octyl- ammonio)propyl chloride or 3(dimethyl-n-hexadecylam- monio)propyl chloride and terminated by silanol functions at both chain ends. They were crosslinked and also incorpo- rated by co-crosslinking into an RTV (room temperature vulcanized) silicone elastomer. Bacteriocidal activities of surfaces of the crosslinked biocidal polysiloxanes and of the elastomers having incorporated these polymers were deter- mined by the colony count method. Thousand-fold reduction of Staphylococcus aureus in contact with the dimethyl-n- octylammonio substituted polymer was achieved in 2 min and in contact with the elastomer containing 20 wt% of this polymer in 15 min, although the density of the QAS was as low as 0.36 mmol/g. The surface structure and properties of the elastomers were studied by XPS, contact angle, AFM and model human serum protein (HSA) adsorption. Water sorption by this material was also studied. The concentration of QAS groups on the elastomer surface depended strongly on the material surroundings. No QAS was found on the surface in ultrahigh vacuum, while a strong enhancement of QAS presence on the surface was observed when it was in contact with water or water vapor. Hydrophobicity of the elastomer surface was little affected by the incorporated biocidal QAS-containing polysiloxane when the elastomer was kept in air. This material showed little ability to adsorb the HSA protein from its aqueous solution. Keywords Biocidal polymers  Antimicrobial polymers  Silicone elastomers  Silicone rubber  Polysiloxanes  Functional polysiloxanes 1 Introduction The defense against the invasion of pathogenic microor- ganisms such as bacteria, fungi, yeasts and algaes has been a serious problem for a long time. These microbes attack humans and animals causing serious infections. They are also the reason of biological fouling and biocorrosion of materials. A great deal of effort has been devoted to pro- tecting polymer materials against pathogenic microorgan- isms and controlling infectious diseases by introduction of covalently-bonded biocidal functions to polymers [1–10]. Among the materials exposed to the adverse action of microbes are silicone elastomers, which are broadly used as gaskets and sealants in baths and other sanitary equipment in bathrooms, such as toilets, hospital rooms and medical offices. Sustainable antibacterial potency of silicone RTV elastomers would be a desirable property. Grafting of biocides on the surfaces of materials or using reactive W. Fortuniak  U. Mizerska  J. Chojnowski (&)  T. Basinska  S. Slomkowski Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland e-mail: jchojnow@cbmm.lodz.pl M. M. Chehimi Interfaces, Traitements, Organisation and Dynamique des Syste `mes (ITODYS), Universite ´ Paris Diderot-CNRS (UMR 7086), 15 rue Jean de Baı ¨f, 75013 Paris, France A. Konopacka  K. Turecka  W. Werel Department of Pharmacy, Chair of Pharmaceutical Microbiology, Gdansk Medical University, Hallera 107, 80-416 Gdansk, Poland 123 J Inorg Organomet Polym (2011) 21:576–589 DOI 10.1007/s10904-011-9485-7