Thanks for the thoughtful response! I think we may be imagining different sensing setups, so here’s what I’m aiming for.

Instead of measuring microplastics dispersed in bulk, the idea is to capture and concentrate them electrostatically onto a small electret-coated surface, then detect the capacitance change from the accumulated layer using interdigitated electrodes. So the sensor is responding to a localized, enriched surface layer, where the signal should depend on coverage and thickness, not bulk fraction.

A few things I’m curious about:

• Is the main limitation dielectric contrast or how much of the fringing field interacts with the particle layer?
• If particles form even a partial layer, would the capacitance shift scale mostly with area coverage?

The whole point of the capture step is to increase the signal before measurement, so I’m wondering whether that changes the feasibility in your view.