Surface plasmon resonance sensor tailored to detect dielectric constants within the range of synthetic polymers

Abstract

Plastic pollution poses a significant environmental concern; however, current methods for identifying and characterising synthetic polymers often require time-consuming procedures or rely on sample degradation. This study demonstrates the direct detection of a broad range of synthetic polymers using Surface Plasmon Resonance (SPR). By tailoring the prism design in the Kretschmann configuration, we extended the dynamic refractive index range of the sensor to encompass typical polymer refractive indices (∼1.49–1.58). Initial validation with refractive index oils confirmed the prism’s ability to detect materials within this range. Subsequently, SPR curves were obtained for nine different polymers, each exhibiting distinctive resonance shifts that may enable polymer-specific identification. Notably, these results also demonstrate SPR’s capability to detect pigmented materials, which is often challenging using other techniques. This direct detection strategy avoids the need for complex spectra analysis procedures, thereby improving measurement efficiency. Finally, we present the potential integration of SPR imaging to explore additional parameters of plastic pollution, paving the way for more comprehensive environmental monitoring and assessment. Our approach holds promise for advancing polymer analysis with SPR by decreasing the analysis time using a direct detection method and expanding the range of materials that can be analysed.