Abstract Composite PVA-PVP films doped with varying concentrations of CoCl 2 were fabricated using the casting technique to develop a low-cost, effective routine dosimeter used in estimating doses in industrial sterilization and food preservation. Although polymeric film dosimeters are widely used, many suffer from moisture sensitivity, which affects their stability and measurement reliability. The influence of ambient humidity and the effectiveness of mitigation strategies remain insufficiently addressed. The prepared films were irradiated using a Cobalt-60 source up to 70 kGy. Structural and optical properties were characterized by FTIR, XRD, TEM, and UV–visible spectroscopy. XRD analysis revealed reduced crystallinity, accompanied by good miscibility of CoCl 2 within the PVA/PVP matrix, as supported by FTIR band variations. UV–VIS spectra showed characteristic absorption bands at 517 and 670 nm, while the optical energy gap decreased from 4.91 to 4.13 eV with increasing CoCl 2 content. Upon irradiation, the films exhibited a progressive color change from pale to deep blue, with dose response dependent on CoCl 2 content. A detailed humidity study demonstrated that ambient moisture has a significant impact on film stability, whereas storage in silica gel effectively preserves its dosimetric performance. Films stored under controlled dry conditions showed superior stability, estimated by 3 %, 6 % pre irradiation and 4 %, 6 % after irradiation in dark and light, respectively. Additionally, in humid environments, the films displayed a distinct blue-to-red color transition, indicating potential application as visual humidity indicator labels. The combined uncertainty (2 σ ) was 4.68 %, suggesting suitability for routine moderate-dose industrial dosimetry.
Sobhy et al. (Tue,) studied this question.