A flexible silicone elastomer/copper oxide nanocomposite for current-mode X-ray dosimetry: Synthesis, characterization, and performance evaluation

Flexible, polymer-based nanocomposite dosimeters have attracted growing interest for radiation monitoring in diagnostic radiology because of their mechanical conformability and potential for low-cost, large-area fabrication. While silicone-based detectors loaded with heavier metal oxides have previously been explored, the dosimetric behavior of room-temperature-vulcanizing (RTV-2) silicone elastomer reinforced with copper oxide nanoparticles — which differs from these systems in both filler chemistry and cure mechanism — has not been systematically characterized. In this work, a flexible silicone/copper oxide nanocomposite was fabricated and evaluated, for the first time, as a current-mode X-ray dosimeter. Copper oxide nanoparticles were synthesized by a simple precipitation method and incorporated into the silicone matrix at weight fractions ranging from 0 to 36.4 wt percent. Structural and chemical characterization confirmed the formation of phase-pure, monoclinic copper oxide nanoparticles with an average crystallite size of 27–29 nm, dispersed within the amorphous silicone network as submicron aggregates (mean Feret diameter 253 ± 86 nm within the composite, from 121 measured particles). Under 60 kV diagnostic X-ray irradiation, the nanocomposite exhibited a stable, nearly linear photocurrent response over a dose-rate range of 2.8–12 mGy/min. Among the compositions evaluated, the sample containing approximately 27.6 wt percent copper oxide showed the best overall dosimetric performance, with a sensitivity of 0.102 ± 0.014 nA/(mGy/min) and a noise-limited detection threshold of 0.25 mGy/min; given that the composition-dependent variation in photocurrent (∼11%) is comparable to the measurement uncertainty, this composition is best regarded as a favorable rather than a definitively optimized formulation. The enhanced sensitivity relative to the unfilled matrix is attributed primarily to the higher photon-interaction probability associated with the increased effective atomic number introduced by the copper oxide phase. The devices showed good short-term repeatability, with a relative standard deviation of 1.01% over repeated irradiation cycles, and a signal-to-noise ratio exceeding 90 at an applied bias of 400 V. These results indicate that silicone/copper oxide nanocomposites constitute a cost-effective, mechanically flexible platform for low-energy X-ray dosimetry, with performance comparable to other polymer–metal oxide systems reported in the literature.