Occupational radiation exposure monitoring is well-established in clinical or industrial environments with various different dosimeter systems. Despite the availability of many dosimetry methods and devices, a challenge with the occasional exposure registration, which may occur due to the spilling of radioactive materials or splitting of these materials in the environment, still exists, because not every individual will have an appropriate dosimeter at the time of the irradiation event. The aim of this work was to develop radiation-sensitive films-color-changing radiation indicators, which can be attached to or integrated in the textile. Polyvinyl alcohol (PVA)-based polymer hydrogels were used as a basis for fabrication of radiation indicator films. Several organic dyes (brilliant carmosine (BC), brilliant scarlet (BS), methylene red (MR), brilliant green (BG), brilliant blue (BB), methylene blue (MB) and xylenol orange (XiO)) were used as a coloring additives. Moreover, PVA films enriched with Ag nanoparticles (PVA-Ag) were investigated. In order to assess the radiation sensitivity of the produced films, experimental samples were irradiated in a linear accelerator with 6 MeV X-ray photons and the radiation sensitivity of irradiated films was evaluated using UV-Vis spectrophotometry method. The most sensitive were PVA-BB films indicating 0.4 Gy-1 sensitivity in low-dose (0-1 or 2 Gy) range. The sensitivity at higher doses was modest. These PVA-dye films were sensitive enough to detect doses up to 10 Gy and PVA-MR film indicated stable 33.3% decolorization after irradiation at this dose. It was found that the dose sensitivity of all PVA-Ag gel films varied from 0.068 to 0.11 Gy-1 and was dependent on the Ag additives concentration. Exchange of a small amount of water with ethanol or isopropanol caused the enhancement of radiation sensitivity in the films with the lowest AgNO3 concentration. Radiation-induced color change of AgPVA films varied between 30 and 40%. Performed research demonstrated the potential of colored hydrogel films in their applications as indicators for the assessment of the occasional radiation exposure.
Keywords: X-ray irradiation; colored films; radiation exposure indicators.