posted on 2024-01-29, 18:05authored byLei Wang, Shaoyun Guo, Xianlong Zhang
γ-Irradiation is a kind of high-energy ionizing
ray, which
has widespread applications in material, food, and medical industries
as well as in the environment. Since this irradiation is invisible,
quantitatively monitoring its exposure doses is crucial to irradiated
targets. As a type of dosimeter, radiochromic dosimeters can detect
γ-irradiation by color changing, and its strategy to realize
the radiochromic behavior basically relies on active radicals from
radiolysis of an external environmental medium. However, the primary
problem of this external environment-mediated sensitization strategy
is that it complicates the components of dosimeters. Herein, we present
a novel type of self-sensitizing radiochromic poly(urethane-urea)
elastomers (PUUEs), where disulfide bonds, serving as radiation-responsive
and sensitizing units, are introduced. This is the first attempt to
utilize radicals generated from radiolysis of weak bonds in a solid
polymer matrix to sensitize color change of dye-doped radiochromic
dosimeters. Moreover, it is intriguing that the simultaneously introduced
aryl hydrazone bond endows dosimeters with excellent color retention
and maintains the Δa* value of 72.9% even after
1 month on the basis of the as-irradiated specimen. Besides, the metathesis
of disulfide bonds not only endows dosimeters with better self-healing
capability, but also accelerates the postcuring behavior and hydrogen
bond reconfiguration, resulting in improved mechanical performance.