How the camel nose improves humidity sensor design

Taking a page from the moisture-detecting capabilities of the camel’s nose, researchers in China designed a new type of humidity sensor that can reliably monitor humidity variations in settings as diverse as industrial exhaust and the air surrounding human skin.

Unlike available humidity sensors, the porous zwitterionic capacitive humidity device offers both high sensitivity to the presence of water and durability under harsh environmental conditions. The design is based on a porous polymer network to mimic the detection capacities of narrow, scroll-like passages within a camel’s nose that create a large surface area. Moisture-attracting zwitterions — molecules that contain an equal number of positively- and negatively-charged functional groups — are layered on to this network to simulate the ability of camel mucus to change capacitance as humidity varies.

The durability of the sensor was demonstrated during tests, which also confirmed its capability to monitor fluctuations in humidity in hot industrial exhaust, find the location of a water source and sense moisture emanating from the human body. The device responded to changes in a person’s skin perspiration during exercise, detected the presence of a human finger and followed its path in a V or L shape.

The researchers from the Chinese Academy of Sciences and Nanchang University suggest the sensor detailed in ACS Nano could also serve as a touch-free interface for interacting with computers.