Printed Low-Cost PEDOT:PSS/PVA Polymer Composite for Radiation Sterilization Monitoring

During the gamma-radiation sterilization process, the levels of radiation exposure to a medical device must be carefully monitored to achieve the required sterilization without causing deleterious effects on itsintended physical and chemical properties. To address this issue, here wehave demonstrated the development of an all-printed disposable low-costsensor that exploits the change in electrical impedance of a semi-interpenetrating polymer network (SIPN) composed of poly(vinyl alcohol)(PVA) and poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PE-DOT:PSS) as a functional polymer composite for radiation sterilizationmonitoring applications. Specifically, the PEDOT:PSS acts as the electricallyconductive medium, while the PVA provides the ductility and stability of theprinted sensors. During irradiation exposure, chain scission and cross-linking events occur concurrently in the PEDOT:PSS and PVApolymer chains, respectively. The concurrent scissoring of the PEDOT polymer and cross-linking of the PVA polymer network leadsto the formation of a stable SIPN with reduced electrical conductivity, which was verified through FTIR, Raman, and TGA analysis.Systematic studies of different ratios of PEDOT:PSS and PVA mixtures were tested to identify the optimal ratio that provided thehighest radiation sensitivity and stability performance. The results showed that PEDOT:PSS/PVA composites with 10 wt % PVAproduced sensors with relative impedance changes of 30% after 25 kGy and up to 370% after 53 kGy (which are two of the mostcommonly used radiation exposure levels for sterilization applications). This composition showed high electrical impedance stability with less than +/- 5% change over 18 days after irradiation exposure. These findings demonstrate the feasibility of utilizing a printing technology for scalable manufacturing of low-cost, flexible radiation sensors for more effective monitoring of radiation sterilization processes