Dielectric and interaction behavior of chitosan/polyvinyl alcohol and chitosan/polyvinyl pyrrolidone blends with some antimicrobial activities

The blends of chitosan, polyvinyl alcohol and chitosan polyvinyl pyrrolidone in dilute acetic acid were found to be compatible by viscosity measurements. The dielectric behavior of the investigated blends were studied using frequency response analyzer covering a frequency range from 10(2) to 10(6) Hz and in a wide range of temperature. The permittivity epsilon' was found to decrease by increasing the frequency showing an anomalous dispersion. The dielectric loss epsilon" data on the frequency domain were found to be broad indicating that more than one relaxation mechanism is present. The data for the whole investigated systems were fitted using Frohlich and/or Havritiak-Negami functions in addition to the conductivity term. The function detected below T-g could be ascribed to an orientation movement related to the side chain. A second function in the lower frequency range could be ascribed as a Maxwell Wagner effect which arises from the interfacial polarization caused by the multi-constituents of the investigated systems. The biological activity of such investigated systems was tested against a representative number of pathogenic organisms by determining the minimum inhibitory concentration (MIC). The activity was found to increase by increasing the amount of CS in the blend. (c) 2005 Elsevier Ltd. All rights reserved.