Cryogels Based on Poly(Vinyl Alcohol)/Ionic Liquids: From Obtaining to Antimicrobial Activity

AbstractThe aim of this study is to determine the suitable conditions for poly(vinyl alcohol) [PVA] cryogels ions loading, aiming to obtain both conductive and antimicrobial gels. Five types of ionic liquids [ILs] have been used: 1-butyl-3-methylimidazolium tetrafluoroborate [BMIMBF4]; 1-ethyl-3-methylimidazolium chloride [EMIMCl]; 1-butyl-3-methyl-imidazolium chloride [BMIMCl]; 1-hexyl-3- methylimidazolium chloride [HMIMCl]; and 1-butyl-3 methylimidazolium tetracloroferrate [BMIMFeCl4]. The influence of the ILs ions kosmotropicity, of their concentration and of the polymer/ILs ratio, on the gel's loading process was studied. The kinetic study of these processes shows that they consist of two simultaneous steps and that they are reversible. PVA/[BMIMBF4], PVA/[EMIMCl], PVA/[BMIMCl], PVA/[HMIMCl], and PVA/[BMIMFeCl4] interaction-type has been discussed based on FTIR spectra and conductimetric measurements. The repartition constants of the ILs between the contact liquids and PVA cryogel have been determined. Antimicrobial activity of PVA/ILs gels against E. coli is correlated with their loading degree. Keywords: Antimicrobial characterControlled releaseIonic liquidsKosmotropyPoly(vinyl alcohol)Repartition constantSwelling/collapse kinetic AcknowledgementWe acknowledge and thank Prof. Dr. Christian Friedrich, from Ludwigs Albert University of Freiburg, Germany, for valuable advice to PhD student Porszolt Attila from Transilvania University of Brasov, Romania, regarding some experimental works.