Flexible PDMS-Based SERS Substrates Replicated from Beetle Wings for Water Pollutant Detection.

Area of Science:

• Materials Science
• Nanotechnology
• Spectroscopy

Background:

• Surface-enhanced Raman scattering (SERS) sensors are crucial for detecting trace analytes.
• Developing flexible and highly sensitive SERS substrates remains a challenge.
• Bionic structures offer unique advantages for sensor design.

Purpose of the Study:

• To create a flexible SERS sensor with a bionic 3D nanoarray structure.
• To optimize silver (Ag) deposition on a polydimethylsiloxane (PDMS) beetle-wing substrate (BWS) for enhanced SERS performance.
• To evaluate the sensor's capability for detecting water pollutants.

Main Methods:

• Replicated technology and thermal evaporation were used to fabricate the bionic 3D nanoarray structure.
• Silver nanoisland thin films were deposited onto a PDMS-BWS, with varying thicknesses (25-40 nm).
• Scanning electron microscopy (SEM), X-ray diffraction (XRD), and contact angle measurements characterized the substrate; rhodamine 6G (R6G) was used for SERS detection.

Main Results:

• The optimized 35 nm Ag deposited on the PDMS-BWS substrate exhibited the strongest SERS intensity.
• The bionic 3D structure generated reproducible three-dimensional hotspots, enhancing Raman signals.
• The sensor showed a 10-fold increase in SERS intensity compared to a pristine substrate with Ag coating.

Conclusions:

• The bionic 3D SERS sensor demonstrates superior sensitivity and reproducibility.
• The flexible sensor shows significant potential for detecting biomolecules and environmental pollutants.
• Future applications include wearable devices and industrial wastewater monitoring.