Subject Number :S-20-KU-0059
Support Type : Common use (including technical support necessary for the training)
Proposal Title (English) : The development of gas sensor based on KB/MIP chemiresistors with fully inkjet-printed processing
Username (English) : YE XIAO
Affiliation (English) :Graduate School of Systems Life Sciences, Kyushu University

1. Summary
Dynamic light scattering measurement on ketjen black were performed using Zeta-potential & particle size analyzer. The purpose to use this instrument is to confirm the size distribution of ketjen black particles in different ink composite.

2. Experimental
Different ink composite, including water, ethanol, isopropanol (IPA), 2-butanol and their mixed solvents, were considered to disperse the ketjen black particle with the assistance of nafion polymer. The ketjen black concentration was diluted to 0.002% for DLS measurements. In addition, all the measurements were performed at 25 ℃. At least three measurements were taken to ensure repeatability of the results.

3. Results and Discussion
For our research, the good dispersed ketjen black ink is used as conductive material for inkjet printing with desktop inkjet printer. To avoid clogging of the nozzle, the ratio between the nozzle diameter and the volume distribution value (D90) from DLS measurements should be at least 50:1. The diameter of the jetting nozzle in our research is 25 µm, so the D90 of ketjen black ink should be below 500 nm.
By comparing the D90 results of different ink composites, a binary ink formulation with 90% 2-butanol and 10% IPA shows good dispersion of ketjen black with D90 of 164.3 nm. In addition, this general ink formulation supports uniform deposition by inkjet printing, enabling scalable fabrication.

4. Others
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5. Publication/Presentation
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6. Patent
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