A frugal automated contact angle analyser for low-cost surface wettability characterization
4 affiliations
- 1School of Engineering, University of Leicester 1 , Leicester LE1 7RH, UK
- 2Institute of Research and Development, Duy Tan University 2 , Da Nang, Vietnam
- 3School of Engineering & Technology, Duy Tan University 3 , Da Nang, Vietnam
- 4Biomedical Engineering Research Group, School of Engineering, University of Leicester 4 , Leicester LE1 7RH, UK
Abstract
Contact angle measurement is a fundamental technique for evaluating surface wettability in materials science, biomedical engineering and coating technologies. However, the high cost of commercial contact angle analysers limits access to surface characterization, particularly in resource-limited laboratories. This study presents a low-cost automated contact angle analyser developed using frugal engineering principles and open-source hardware. The system integrates Arduino-based control, NEMA 17 stepper-motor actuation, automated microdroplet dispensing, smartphone-based optical imaging and a 3D-printed polylactic acid (PLA) framework. A calibrated 330-step dispensing cycle generated reproducible 5 μl water droplets, with fixed optical alignment minimized operator variability. Wettability measurements were performed on polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC) and aluminium substrates and analysed using ImageJ. Mean contact angles were 108.5° for PTFE, 73.9° for PVC and 85.8° for aluminium, closely matching published literature values. One-way analysis of variance (ANOVA) demonstrated significant differences between substrates (p < 0.001), with measurement variability of ±2.3° indicated good repeatability. The total fabrication cost was £114.26, representing approximately 99% cost reduction compared with commercial instruments. The proposed platform demonstrates that automated, reproducible surface wettability characterization can be achieved using low-cost, open-source instrumentation, providing an accessible solution for research, education and engineering laboratories while broadening access to advanced materials characterization.
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BibTeX
@article{coelho2026frugal,
title = {{A frugal automated contact angle analyser for low-cost surface wettability characterization}},
author = {Rodrigo G. Martins Coelho and Andy Truman and Saravana Kumar Jaganathan},
journal = {Royal Society Open Science},
year = {2026},
month = nov,
doi = {10.1098/rsos.261464},
url = {https://royalsocietypublishing.org/rsos/article/13/11/261464/484056/A-frugal-automated-contact-angle-analyser-for-low},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - A frugal automated contact angle analyser for low-cost surface wettability characterization
AU - Rodrigo G. Martins Coelho
AU - Andy Truman
AU - Saravana Kumar Jaganathan
PY - 2026
DA - 2026/11/04
JO - Royal Society Open Science
DO - 10.1098/rsos.261464
UR - https://royalsocietypublishing.org/rsos/article/13/11/261464/484056/A-frugal-automated-contact-angle-analyser-for-low
AB - Contact angle measurement is a fundamental technique for evaluating surface wettability in materials science, biomedical engineering and coating technologies. However, the high cost of commercial contact angle analysers limits access to surface characterization, particularly in resource-limited laboratories. This study presents a low-cost automated contact angle analyser developed using frugal engineering principles and open-source hardware. The system integrates Arduino-based control, NEMA 17 stepper-motor actuation, automated microdroplet dispensing, smartphone-based optical imaging and a 3D-printed polylactic acid (PLA) framework. A calibrated 330-step dispensing cycle generated reproducible 5 μl water droplets, with fixed optical alignment minimized operator variability. Wettability measurements were performed on polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC) and aluminium substrates and analysed using ImageJ. Mean contact angles were 108.5° for PTFE, 73.9° for PVC and 85.8° for aluminium, closely matching published literature values. One-way analysis of variance (ANOVA) demonstrated significant differences between substrates (p < 0.001), with measurement variability of ±2.3° indicated good repeatability. The total fabrication cost was £114.26, representing approximately 99% cost reduction compared with commercial instruments. The proposed platform demonstrates that automated, reproducible surface wettability characterization can be achieved using low-cost, open-source instrumentation, providing an accessible solution for research, education and engineering laboratories while broadening access to advanced materials characterization.
SN - 2054-5703
ER -