Dielectric properties: a gateway to antibacterial assay-a case study of low-density polyethylene/chitosan composite films

The dielectric properties of low-density polyethylene-chitosan composite films were correlated with their antibacterial properties in this work. Films were designed on the molecular level using palm oil as a plasticizer in an internal mixer. Maleic anhydride and dicumyl peroxide were used as a coupling agent and a free radical initiator, respectively. The dielectric properties of the composite films were studied as a function of chitosan loading, presence of plasticizer and variable applied frequency. The dielectric constant of the samples was positively correlated with the amount of chitosan in the polythene matrix. The antibacterial properties of the composite films were also studied. A distinct inhibitory zone against Escherichia coli and Staphylococcus aureus developed, and this zone increased in diameter with chitosan loading. The low-molecular-weight chitosan-based polyethylene films showed significant improvement in dielectric and antibacterial properties when compared with the native chitosan-based films. These studies show that the antibacterial properties of the developed films were complementary with their dielectric properties. This study suggests the possibility of using the dielectric properties of composites as a measure of their antibacterial properties.