Simulation of Optical Planar Waveguide Sensor for Microplastics Detection in Water

Nowadays, microplastics pollution has become a global concern as it endangers the ecology, marine animals, and cause health threats to human beings. This paper attempted to simulate an optical planar waveguide sensor for microplastics detection in water via Wave Optics Module-COMSOL Multiphysics®. The analyte refractive index was ranged from 1.4800 to 1.5000 RIU, in reference to the microplastics refractive index. The simulation results showed significant variations in the evanescent waves of the sensor at different analyte refractive indices, thus proving that the sensor has potential for microplastics detection in water with sensitivity of 0.0040 in dimensionless unit.

I. Introduction

Plastics have wide applications across practically all industries worldwide and are extremely useful in everyday life, for example as packaging materials, food storage, and drinking bottles. However, improper disposal of postconsumer plastics, either to be recycled or reused, may lead to environmental pollution. Plastics in water bodies such as rivers, oceans, and lakes will degrade to form microplastic fragments [1], eventually resulting in microplastic invasion of water. This consequence not only endangers aquatic animals but also risks human health.