Here, the development
of highly porous colorimetric indicators
that are able to rapidly sense the presence of amine vapors is presented.
Specifically, porous, curcumin-loaded polycaprolactone fibers are
formed by electrospinning through non-solvent-induced phase separation.
In comparison to the non-porous fibers, the developed system shows
significantly higher sensitivity and responsivity to the presence
of dimethylamine vapors, with a distinct color change at very low
vapor concentrations (2.33 ppm compared to 9.26 ppm) within the first
5 s of exposure. Indeed, CIELAB analysis proves that the induced color
changes can be easily perceived visually, as the differences between
the initial and the final color of the indicator after its interaction
with the modified environment are well above the limit for visual
perception, even by inexperienced users. Furthermore, the color changes
are reversible, enabling the use of the same indicator several times,
making it, thus, a sustainable colorimetric indicator system that
can be used in applications where the rapid detection of low concentration
of alkaline vapors is necessary.