A multidisciplinary team at KAUST has created a sensor that can hitch a ride on aquatic animals, and measure the ocean’s shifting salt levels. It’s lightweight, robust, flexible, and can function after long periods of submersion.
According to the researchers, the salinity sensor can “form the basis of a marine animal monitoring device that records multiple underwater habitat
Ocean salinity can impact marine organisms’ health, water circulation, and other key aspects of ocean life.
“It is a pivotal parameter used to study properties of the oceans as well as the effects of climate change,” explains Alayna Kaidarova, a Ph.D. student who is part of the KAUST’s Sensor Initiative working at their Red Sea Research Center.
If salt levels are high, then electrical conductivity goes up as well, which can be measured with a pair of electrodes. However, there exists a unique challenge—microorganisms grow on the electrode surface, known as biofouling, which causes the conductance values to drop.
To overcome the microorganism conundrum, the KAUST sensor is made of a flexible polymer sheet. “Writing on the sheet using a laser beam, the team heated targeted strips of the polymer, breaking down the polymer structure to produce conductive strips of graphene that form the electrodes,” according to KAUST.
When the sensor was operating at a low frequency, the dip in conductance values occurred again due to biofouling. That all changed when operations switched to a high frequency. Biofouling had no effect on the sensor’s performance, and readings were steady even after weeks at sea.
“We avoided the influence of foulants’ recruitment on the surface of the electrodes, which is expected to solve long-term reliability issues,” Kaidarova says.
The researchers aim to utilize the laser-induced graphene technique to develop integrated sensor platforms in a versatile and cost-effective way. In addition to salinity, these platforms can measure aspects such as pressure, pH, temperature, and magnetic field.
Read the article, “Flexible and Biofouling Independent Salinity Sensor,” published in Advanced Materials Interfaces, to learn more.