PDMS-based RF Resonant Sensor for Measuring the Concentration of Micro-Plastics

Recently, microplastics have become a big problem, but conventional particle analyzers that can detect microplastics require a lot of time and cost, so in this paper, in order to solve this issue, a low-cost RF sensor was designed to detect microplastics through it. The RF sensor was designed using the L-C-L resonance structure, and the microplastic concentration was detected through the change of the dielectric constant by collecting microplastic in the dielectric space between the capacitors. Through the RF sensor designed in this study, it was confirmed that microplastics as small as 0.1% can be detected, and it was confirmed that a single particle can be distinguished through a readout circuit.

I. Introduction

Recently, microplastics have become a problem in most of the natural world, such as the ocean, soil, and atmosphere [1] [2]. Microplastics defined as synthetic polymer compounds mean less than 5 mm, which is about the size of a pellet, and are classified into primary microplastics that are intentionally manufactured and used, and secondary microplastics that are naturally fragmented through physical/chemical decomposition processes. ISO/TR 21960:2020 [3] defines or more as microplastics and less than as nanoplastics, but OECD and ECHA regulates less than as nanoplastics. Microplastics are composed of polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), and nylon.