Who
Dr. Shan Jiang's research group in the Department of Materials Science and Engineering at Iowa State University, Ames, Iowa, USA. The group works on surface, interface and coating materials, including waterborne antimicrobial coatings.
Case Study
Written by
Abhimanyu Bhandankar
Holds an MBA from Schulich School of Business and a BE in IT. He joined Droplet Lab in July 2019 and now leads sales and marketing.
CEO at Droplet Lab
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Technical Review by
Gurdeep Singh Saini
Holds a BASc in Mechanical Engineering from Ryerson University (now Toronto Metropolitan University) and an MASc from York University. He develops the automatic edge and baseline detection behind the Dropometer's analysis.
COO at Droplet Lab
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Executive Summary
Problem
The group needed wetting measurements on its own coated samples, many of them small pieces of coated fabric, tested with water and with oils. The only contact angle instrument available was an older shared instrument in the department.
Solution
A Dropometer with the automatic dropper, a motorised tilting stage for roll off measurements and a fabric holder, bought directly from Droplet Lab after the group met the team at the ASEE annual conference in June 2025, with remote training for the group's researchers.
Time to Value
23 June 2025: met at the ASEE annual conference. August 2025: university IT review of the software. 8 September 2025: purchase orders issued. 9 October 2025: instrument delivered, with remote training on 10 and 15 October. 11 November 2025: group confirmed the full setup works. 17 June 2026: paper published online.
Results
The instrument has been in the group's lab since October 2025. Researchers measure contact angle on small coated fabric samples, using the supplied fabric holder and holders they 3D printed for their own sample sizes, and roll off on the tilting stage. The group's 2026 paper on rechargeable antimicrobial coatings in ACS Applied Materials & Interfaces used the Dropometer.
Iowa State University, at a glance
Research focus
Surface, interface and coating materials, including waterborne antimicrobial coatings.
Products / applications
Functional coatings on fabrics and other surfaces.
Measurement stage
Laboratory research on coated samples.
Users
A PhD candidate runs the instrument day to day, with other researchers in the group.
Materials and surfaces tested
Small coated fabric samples, tested with water and with oils.
Key constraints
Soft, porous samples that must be held flat; several test liquids; a research budget.
The challenge: measuring wetting on coated fabrics, in the lab that makes them
A coating that repels or kills microbes is only as good as its surface, and fabric is a hard surface to measure.
Why coatings need wetting data
Whether a coating repels water and oil, or lets a cleaning solution reach the surface, shows up first in how a drop sits and slides on it. Contact angle tells the group where a surface sits on the hydrophobic to hydrophilic scale, and roll off shows how easily a drop leaves it. Textile teams ask the same questions in water repellency testing for DWR finishes.
Why fabric is hard to measure
Fabric is soft and porous and rarely lies flat. Unless the sample is held flat and level under the drop, the baseline is wrong and so is the angle. Rough, fibrous surfaces also change the apparent angle, as our Wenzel and Cassie Baxter roughness experiment shows. Other Dropometer users have met the same effect, for example in this study of hydrophobic electrospun polystyrene fibres. Our guide to contact angle on fabrics covers sample preparation.
Why the group wanted its own instrument
The department had an older shared contact angle instrument. Having one in the group's own lab meant measuring samples as they came off the coating bench, with water and with oils. Measuring in house also lets one trained person keep the method the same from sample to sample, which is the core of reproducible contact angle measurement. For labs weighing the same choice, see our guide to contact angle goniometers for advanced research.
What success would require
A way to hold small fabric samples flat, a consistent drop from an automatic dropper, and a tilting stage for roll off, all on one portable instrument the group's researchers could run themselves. Drop based textile methods such as AATCC TM 79 for textile absorbency time how a drop soaks in. A sessile drop contact angle measurement adds the angle itself.
The insight: put the drop measurement next to the coating bench
What Was Deployed
Delivered configuration (October 2025): the Dropometer contact angle kit with the automatic dropper, a manual syringe as a backup, a motorised tilting stage for sliding and roll off angles, and the fabric holder.
The group measures small pieces of coated fabric with water and with oils, entering the liquid density in the app for each oil. Because the supplied holder did not suit every sample size, the group 3D printed its own holders to fit. For wetting values measured by other labs, see our open dataset of client collected wetting measurements.
The Origin
From a conference booth to a coatings lab
Dr. Shan Jiang met the Droplet Lab team at the ASEE annual conference on 23 June 2025. The request was a quote for the research group in Materials Science and Engineering, with the automatic dropper, the tilting stage and a fabric holder.
The software went through the university's IT review in August. The purchase orders followed on 8 September, and the instrument reached the lab in Ames on 9 October 2025. Droplet Lab trained the group's researchers in remote sessions on 10 and 15 October and 7 November.
In the first weeks Droplet Lab took back and adjusted the automatic dropper and tilting stage, and returned them in early November. When the tilting stage needed attention again in May 2026, it was fixed on a video call with Droplet Lab's engineers.
Before vs After
Rollout timeline
Timeline (high level)
June 2025: First contact
Met the Droplet Lab team at the ASEE annual conference (23 June)
August to September 2025: Purchase
- University IT review of the software (August)
- Purchase orders issued (8 September)
October 2025: Delivered and trained
- Instrument delivered to the lab in Ames (9 October)
- Remote training sessions on 10 and 15 October
November 2025: Adjusted
- Automatic dropper and tilting stage adjusted by Droplet Lab and returned (early November)
- Final remote onboarding session (7 November)
- Group confirmed the setup works (11 November)
May 2026: Support call
Tilting stage fixed on a video call with Droplet Lab engineers (8 May)
June 2026: Published
Antimicrobial coatings paper published online in ACS Applied Materials & Interfaces (17 June 2026, July 2026 issue)
Proof and validation: what is published so far
Test method
Contact angle on coated samples with the Dropometer (Droplet Lab, Canada), in the group's own lab, plus roll off on the motorised tilting stage. The measurement conditions used in the 2026 paper are not yet reported on this page.
Sample size and operators
Measurements by researchers in the group, trained remotely by Droplet Lab in October and November 2025.
Repeatability / reproducibility
Not yet reported.
Notes / assumptions
Source: R. Ortega, Z. Yang, S. Demirci, T. A. Twedt, U. K. Dey, F. Liu, T. S. M. Rawah, N. Resende De Macedo, J. C. Mora Diaz, L. G. Gimenez Lirola, S. Jiang, 'Core Shell Nanoparticle Additive Enables High Efficacy Antimicrobial Coatings', ACS Applied Materials & Interfaces 18 (2026) 35959 to 35969, doi:10.1021/acsami.6c05097. The abstract reports a core shell particle that cuts the amount of costly hydantoin acrylamide monomer by about 65% while keeping antimicrobial performance, in waterborne coatings that can be recharged with dilute bleach.
Outcomes to date
Measured Outcomes
2026
Published
Rechargeable antimicrobial coatings paper that used the Dropometer (Ortega et al., ACS Applied Materials & Interfaces 18 (2026) 35959 to 35969).
3D printed
Custom sample holders
The group 3D printed its own holders to fit its fabric sample sizes, alongside the supplied fabric holder.
Water and oils
Test liquids
With the liquid density set in the app for each oil.
Operational Outcomes
In house
Wetting measured in the group's own lab instead of on a shared departmental instrument.
One instrument
Contact angle and roll off on the same portable instrument.
Supported
Remote training and fixes from Droplet Lab's engineers by video call.
In the client's words
I spoke with my group about their experience using the setup. They appreciate the software and the compact design.Dr. Shan Jiang - Assistant Professor, Materials Science and Engineering, Iowa State University
What's next
Delivered
Research Dropometer with automatic dropper, tilting stage and fabric holder (October 2025)
Rechargeable antimicrobial coatings paper (ACS Applied Materials & Interfaces, 2026)