Concept and design of ReSURF by
microphase separation. a Schematic illustration showing the
fabrication of ReSURF. b Schematic illustration of a ternary phase
diagram. Triggered by solvent evaporation, the system micro-separates into a
1H,1H,2H,2H-perfluorodecyltrimethoxysilane (FAS) surface structure-rich domain
and a polymer-rich domain, with the surface microphases self-assembling into
versatile and highly tunable morphologies. The FAS surface microphase
substantially increases surface roughness and hydrophobicity, while the
underlying polymer matrix endows ReSURF with softness, stretchability, and a
high κ. Both domains not only play distinct roles in this system but also
synergize with each other to enhance device performance. c SEM images comparing the surface morphology
of the 2.5 wt% FAS material with pure poly(vinylidene
fluoride-co-hexafluoropropylene) (P(VDF-HFP)). The left image shows that the
contact angle increases with the surface structure of FAS. Credit: Nature Communications (2025). DOI: 10.1038/s41467-025-59973-y
Clean,
safe water is vital for human health and well-being. It also plays a critical
role in our food security, supports high-tech industries, and enables
sustainable urbanization. However, detecting contamination quickly and
accurately remains a major challenge in many parts of the world.
A new device developed by researchers at
the National University of Singapore (NUS) has the potential to significantly
advance water quality monitoring and management.
Taking inspiration from the biological
function of the oily protective layer found on human skin, a team of researchers led by Associate Professor
Benjamin Tee from the Department of Materials Science and Engineering in the
College of Design and Engineering at NUS translated this concept into a
versatile material, named ReSURF, capable of spontaneously forming a
water-repellent interface.
The team's design of the ReSURF material
and performance of the novel water quality sensor are published in Nature
Communications.
This new material, which can be prepared
through a rapid micro-phase separation approach, autonomously self-heals and
can be recycled. The researchers incorporated the material into a device known
as a triboelectric nanogenerator (TENG), which uses the energy from the
movement of water droplets to create an electric charge. The resulting device
(ReSURF sensor) can be applied as a water quality monitor.
"The ReSURF sensor can detect various pollutants, such as oils and fluorinated compounds, which are challenging for many existing sensors. This capability, together with unique features such as self-powered, self-healing, reusability and recyclability, positions ReSURF as a sustainable solution for real-time, on-site, and sustainable water quality monitoring," said Assoc. Prof. Tee.
Credit: National University of Singapore
Rapid and sustainable water quality sensing
Existing water quality monitoring
technologies such as electrochemical sensors, optical detection systems, and
biosensors are effective in certain specific applications, such as detecting
heavy metals, phosphorus, and microbial pollution.
However, these technologies often
face limitations including slow response, high costs, reliance on external
reagents or power sources, limited reusability, and the need for bulky
laboratory equipment or specialized instrumentation.
The ReSURF sensor developed by the
NUS team effectively overcomes these challenges, particularly in on-site
real-time water quality sensing. The self-powered device has demonstrated the
ability to detect water contaminants in approximately 6 milliseconds (i.e.
around 40 times faster than a blink of the eye).
Additionally, the ReSURF sensor is
designed to be self-healing and recyclable, making it a sustainable and
low-maintenance solution. Being stretchable and transparent, the material can
be easily integrated into flexible platforms, including soft robotics and
wearable electronics, setting it apart from conventional sensing materials.
Furthermore, the ReSURF material
applied as a sensor offers an environmentally friendly solution, as it can be
easily recycled due to its solubility in solvents, enabling it to be reused in
new devices without suffering a loss in performance.
ReSURF sensor: How it works
The ReSURF sensor monitors water
quality by analyzing the electrical signals generated when analytes—such as salts, oils, or
pollutants—in the water droplets contact its surface.
When water droplets containing
analytes strike the water-repellent surface of the sensor, they spread out and
slide off quickly, generating electric charges within milliseconds.
The magnitude and characteristics
of the signal generated would vary according to the composition and
concentration of the analytes present. By monitoring these signals in real
time, the ReSURF sensor can rapidly and accurately assess water quality without
the need for external power sources.
To demonstrate its capabilities,
the researchers tested the ReSURF sensor on a pufferfish-like soft robot to
detect oil in water and perfluorooctanoic acid—a common contaminant found in
water sources.
The test produced promising results
with both contaminants producing different voltage signals, providing a
proof-of-concept that the ReSURF sensor can be used in early surveillance of
possible contamination.
Safeguarding water quality
The ReSURF sensor offers broad
application potential. It can be deployed in rivers, lakes, and reservoirs to
enable early surveillance of pollutants, allowing for quick response to water
contamination emergencies.
In agriculture, it is capable of
monitoring water safety in areas like rice fields. In industrial settings
and sewage treatment plants, the ReSURF sensor could provide valuable insights
for wastewater management.
The research team hopes to optimize
the ReSURF sensor by enhancing the specificity of pollutant detection,
integrating wireless data transmission capabilities, and scaling the system for
long-term or large-scale environmental monitoring.
Additionally, the researchers plan
to explore more eco-friendly material alternatives to enhance sustainability
and align with evolving environmental regulations.
"Future iterations could integrate additional sensing modalities or machine learning–based signal analysis to enable more precise identification and classification of pollutants. We envision this platform as a foundation for the development of more intelligent and responsive water quality monitoring systems," said Assoc. Prof. Tee.
Source: ReSURF: Stretchable, self-healing water quality sensor enables ultrafast surveillance
No comments:
Post a Comment