  Artificial membranes that are sensitive to temperature are needed in robotics
to augment interactions with humans and the environment and in bioengineering
to improve prosthetic limbs. Existing flexible sensors achieved sensitivities
of <100 mK and large responsivity albeit within narrow (<5 K) temperature
ranges. Other flexible devices, working in wider temperature ranges, exhibit
orders of magnitude poorer responses. However, much more versatile and
temperature sensitive membranes are present in animals such as pit vipers,
whose pit membranes have the highest sensitivity and responsivity in nature and
are used to locate warm-blooded preys at distance. Here, we show that pectin
films mimic the sensing mechanism of pit membranes and parallel their record
performances. These films map temperature on surfaces with a sensitivity of at
least 10 mK in a wide temperature range (45 K), have very high responsivity,
and detect warm bodies at distance. The produced material can be integrated as
a layer in artificial skins platforms and boost their temperature sensitivity
to reach the best biological performance.
