Polymeric Films Containing Sodium Chlorite That Release Disinfectant Gas upon Activation with UV Light

Polymeric films that release disinfectant gas on demand have the potential to be useful for management of microbial burden (e.g., sterilization). Past attempts to create such films, however, have suffered from the need for stringent control over moisture or exposure to visible light prior to use. It is reported that polyvinyl alcohol (PVA) or polyolefin (POD) films that contain NaClO2 crystals can release ClO2 gas upon UV-activation and exposure to moisture. In addition to showing that the concentration of gaseous ClO2 released from the polymeric films is sufficiently high for antimicrobial activity, fundamental insights into factors controlling ClO2 release are provided by using atomic force microscopy, optical microscopy, Raman microscopy, and time-of-flight secondary ion mass spectrometry. Specifically, by determining the sizes of the polymer-dispersed NaClO2 particles, support for the hypothesis that UV light activates an interfacial layer of the NaClO2 crystals to generate ClO2 is obtained. Additionally, it is found that the half-life of the UV-activated state of NaClO2 depends on the reactivity of the polymer matrix. Because both PVA and POD possess properties analogous to polymers used in packaging films, it is concluded that the approach described in this study may enable introduction of deodorizing or antimicrobial functional properties into polymeric packaging.