Newswise — The National Science Foundation has awarded University of Wisconsin-Milwaukee scientists $1.5 million to perfect a method of mass-producing small water sensors using inkjet printing.

The goal is to determine whether the process, which is similar to how inkjet printers deposit ink on paper, can be customized in order to scale up production and do it more economically than traditional manufacturing methods.

The graphene-based water sensors, developed at UWM, outperform current technologies for accuracy, sensitivity and sensing speed. Their performance and size make them useful for continuously monitoring drinking water for miniscule traces of contaminants such as lead.

The grant will help researchers engineer the ink, which will contain the nanomaterials that give the sensors their capabilities. The ink is then layered on top of the sensors’ plastic substrate.

The project is led by Deyang Qu, UWM’s Johnson Controls endowed professor, in collaboration with Northwestern University and UW-Madison.

While printing with graphene, a conductor, has been demonstrated successfully, printing with graphene oxide, a semiconductor, has been studied less, said Junhong Chen, UWM distinguished professor of mechanical engineering who developed the sensor platform.

Because the two materials exhibit different properties, engineering the ink containing graphene oxide and various chemical probes will require some fine-tuning, said Chen.

In addition to engineering inks containing various materials, the researchers will have to integrate components at different scales.

The performance of the printed sensors will be tested by companies, including the startup NanoAffix Science LLC, founded by Chen. The results may be applicable to cost-effective manufacturing of other printable, flexible electronics such as solar cells, lithium-ion batteries and supercapacitors.