Even
a small amount of harmful liquid/gas leakage is hazardous
and probably leads to extraordinarily dangerous situations. To effectively
control the storage of harmful liquids/gases, the monitoring of leakage
is thus highly important. Herein, we develop an indicator film that
can easily respond to harmful hydrophilic liquids and gases and allow
for the visual recognition of a transparency transformation involving
hydrated poly(N-isopropylacrylamide). The normalized
transparency of the indicator film is 100% when it is wet and below
10% when it is triggered by hydrophilic liquids and gases. The pH
paper-like indicator film responds to some harmful hydrophilic liquids
and gases in the chemical laboratory, including alcohols, ketones,
aldehydes, acid solutions, their corresponding vapors, and some gases.
The response to hydrophilic liquids and gases by the indicator film
is attributed to competition between hydrophilic molecules and poly(N-isopropylacrylamide) in absorbing water. This work not
only provides an understanding of the adsorption and diffusion of
gases and liquids on surfaces but also affords promising applications
for monitoring chemical industry and chemical laboratory environments,
general pollution levels, and indoor air quality.