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Updated: Feb 1, 2026

Spray-Coated Melanin/PEDOT:PSS Films for Sustainable Organic Electrochemical Transistors
Published on: October 28, 2025
High-speed Fizeau interferometry for film topography measurement during spray film interaction
Leif Schumacher1, Kevin Seel1, Manuel A Reddemann1
1Institute of Heat and Mass Transfer, RWTH Aachen University, Augustinerbach 6, 52062 Aachen, Germany.
Abstract:
This work presents a novel high-speed interferometric thickness measurement system for thin films (1 μm-23 μm). The system is based on a Fizeau-interferometer and combines a high-speed camera for 2-D topographic fringe images with a spectrally resolved white light interferometer. The aim of this combination is to overcome the ambiguities of the phase demodulation process during fringe pattern analysis. The system is able to measure spatially and temporally resolved film thickness distributions during fast processes. The measurement error of the system is around 5% compared to a commercial 0-D interferometer. First, the results during a diesel spray impingement onto a predefined diesel film are shown, and at the impingement point, an increase in a fluid volume of 24.3% can be seen.
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