Photonic
crystal-based ethanol concentration indicators with rapid
response and brilliant structural color output definitely take a place
in colorimetric sensors. Here, based on the H-bond-regulated swelling
of acrylate shape memory polymers (SMPs) and the solvent-induced structural
color change of the double inverse opal photonic crystals (DIOPCs),
new-type photonic crystals (PCs) colorimetric indicators were constructed,
exhibiting a span of maximum reflection wavelength (λmax) up to ∼166 nm in response to alcohols with concentrations
from 0 to 100 vol %. DIOPC indicators (DIOPCIs) show a rapid response
to alcohols (<1.5 s) and output different structural colors (covering
from blue to red). The colorimetric sensing mechanism includes the
solvent-triggered recovery of the inverse opal skeleton, the cosolvency
effect and H-bonds induced swelling/shrinkage of the polymer, the
phase separation between polystyrene (PS) microsphere and polymer
skeleton, and the light diffraction of DIOPCs. While ensuring a larger
λmax span by regulating the H-bond interactions in
polymer chains through acrylamide (AAm), AAm-modified DIOPCIs are
sensitive to some specific ethanol concentrations. The real-time sensing
of ethanol concentration during fermentation verified the practicability
of DIOPCIs, thus establishing a visual model between structural color
and corresponding fermentation kinetics. We envisage that the DIOPCIs
will contribute to the intelligentization of the alcoholic fermentation
and distillation industry.