Contents
Functional, Medical and Electronic Coatings

Dental Implant Surface Treatment QC: Contact Angle on Each Implant Surface, From SLA Surface to Modified Titanium Surface Topographies

Implant surface treatment sets how water, blood and cells first meet the implant, and fresh titanium surfaces lose wettability as they age. Measure water contact angle on every treatment and lot with a locked method, and read it alongside roughness and surface chemistry.

Who this is for: Dental and orthopedic implant makers, surface treatment and quality engineers, and implant dentistry and biomaterials researchers.

Where it fits: Comparing surface treatments, lot release checks after cleaning and packaging, shelf life studies, and research on cleaning or decontaminating implant surfaces.

What it does not do: It does not measure roughness, surface composition, sterility, biocompatibility or bone response.

Method
Sessile drop water contact angle at a fixed read time; advancing and receding angles; surface energy from two or three liquids
Standard
Follows ASTM D7334 practice; supports surface characterization under ISO/TS 10993-19 and FDA dental implant guidance
Setup
About 2 minutes
Book a 15 minute demo Request a quote
Teeth, implants, and dental instruments
Abhimanyu Photo
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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Droplet-Lab logo
Technical Review by
Droplet Lab Team
Droplet Lab builds precision instruments and software for surface science measurement, specialising in contact angle analysis and surface tension characterisation. Used by researchers across materials science, pharmaceuticals, coatings, and advanced manufacturing, Droplet Lab's Dropometer has contributed to studies published in peer-reviewed journals including Advanced Functional Materials (Impact Factor 19). The team combines instrument engineering with deep domain knowledge in wettability science with a focus on practical accuracy.
Read More
Abhimanyu Photo
Written By

Abhimanyu Bhandankar

CEO at Droplet Lab

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.

Droplet-Lab logo
Reviewed By

Droplet Lab Team

Droplet Lab builds precision instruments and software for surface science measurement, specialising in contact angle analysis and surface tension characterisation. Used by researchers across materials science, pharmaceuticals, coatings, and advanced manufacturing, Droplet Lab's Dropometer has contributed to studies published in peer-reviewed journals including Advanced Functional Materials (Impact Factor 19). The team combines instrument engineering with deep domain knowledge in wettability science with a focus on practical accuracy.

Featured Studies & Publications

Research Paper Contact angle measurement with a smartphone
Research Paper Surface tension measurement with a smartphone using a pendant drop
Why it matters

Why implant surface wettability matters

139.9° vs 0°

dynamic water contact angle of a sandblasted, acid etched (SLA) titanium surface against the same surface chemically modified to be hydrophilic.

Rupp et al., J Biomed Mater Res A 76A:323, 2006

0° to about 90°

water contact angle of new against old titanium surfaces; losses in biological capability persisted for up to six months of ageing.

Minamikawa et al., Materials 9(2):102, 2016

84.8° to 65.3°

change in water contact angle on SLA titanium discs after one cleaning brush, across 125 measurements comparing four brushes.

Alabbad, Silikas and Thomas, Dental Materials, 2025

Sources: Rupp F. et al., Enhancing surface free energy and hydrophilicity through chemical modification of microstructured titanium implant surfaces, Journal of Biomedical Materials Research A, 2006; Minamikawa H. et al., Long term progressive degradation of the biological capability of titanium, Materials, 2016; Alabbad M., Silikas N., Thomas A., Effect of mechanical instrumentation on titanium implant surface properties, Dental Materials, 2025. Figures come from these sources, not from Droplet Lab measurements.

Quick reference

What this implant surface check does and what it does not

A quick reference for implant makers and researchers checking fit before reading further.

Evidence Box

Problem this solves

Implant surface treatments and lots released on roughness and appearance alone, with no record of how the surface wets or whether it has aged.

Standards

ASTM D7334 covers advancing contact angle practice; ISO/TS 10993-19 covers physico chemical and topographical characterization of materials.

Peer reviewed method

The Dropometer drop shape method was validated against a KRUSS DSA100E in two peer reviewed papers, in Review of Scientific Instruments and Colloids and Surfaces A.

Customer case study

A University of Manchester group measured SLA titanium discs after four cleaning brushes, 125 measurements in all, and published in Dental Materials (2025).

Published research

Harvard and Institute of Science Tokyo researchers found plasma treatment cut water contact angle on titanium from 83.1° to 24.1° (Biomimetics, 2025).

Honest limit

Contact angle does not predict osseointegration on its own. Pair it with roughness, chemistry and biological tests.

Who this is for

What implant surface question are you trying to answer?

Pick the card closest to your role. Each one points to the part of this page that answers it.

Implant quality or process engineer

You release titanium implant and ceramic implant lots after blasting, etching, cleaning and packaging. A water contact angle on witness coupons or implants from each lot shows whether the surface treatment and cleaning ran as validated, giving the good surface for bone contact you designed.

Set gates from your validated lots, measured with the same method.

Surface treatment R&D

You develop surface modification for titanium dental implant and ceramic surfaces, testing different surface modifications from SLA and anodized surfaces to bioactive surface coatings and other implant surface modifications, and need to see the influence of surface treatment on wetting. Contact angle and surface energy compare each treatment on the same implant material.

Report read time, liquid and storage age with every value.

Implant dentistry researcher

You study how cleaning, decontamination or coatings change the surface of dental implants, for example in the implant treatment of peri implantitis, as the Manchester and Harvard groups did. Contact angle records each change before you run cell or bone studies.

Compare with an untreated control from the same batch.
Fit check

Is this the right check for your implant surfaces?

It measures how liquids meet the implant surface. It does not measure the bone response.

Good fit if

You compare a variety of surface treatments on titanium or zirconia, or various implant designs.
You check implant surfaces after cleaning, packaging or storage.
You study ageing or contamination of the implant surface.
You test decontamination or cleaning of a failing implant surface in the lab.
You report surface wettability with other surface analysis in papers.

Less relevant if

You need average surface roughness; use profilometry or interferometry.
You need surface composition; use XPS or EDS.
You need sterility or biocompatibility results.
You need to measure on implant threads directly without a flat area or coupon.
Summary

How contact angle supports dental implant surface QC

The answer in under a minute.

Measure water contact angle on different surface treatments and on each lot at a fixed read time, on witness coupons or flat areas, and compare with a validated reference. Track it over storage time, because fresh titanium surfaces lose wettability as they age, and read it with roughness and surface chemistry.

The Dropometer contact angle and surface energy kit runs the measurement. Our contact angle measurement guide, captive bubble method entry and surface free energy calculator explain the methods. A University of Manchester group measured cleaned SLA titanium, and a University of Maryland dental group measured an antibacterial resin coating. Our medical device guide covers the sector.

Expert Quote

Expert perspective on wettability

A contact angle is a thermodynamic property: fix the liquid and the solid and the same angle appears whether the drop sits on a plate or climbs a capillary.

Dr. Alidad Amirfazli

Professor, Department of Mechanical Engineering, York University; Co-founder, Scientific Advisor, Droplet Lab

The problem

Why implant surface treatment is hard to control by wettability

Dental implants succeed when bone grows onto the implant surface. In the field of dental implantology, osseointegration of dental implants depends on how bone and implant meet: the bone implant interface forms on the surface layer, so the features of the implant surface shape early implant integration. Implant success also depends on implant placement, implant length, implant site and loading, but the surface is the part a maker controls at release. Surface treatment of dental implants is how makers shape that first contact: a machined, sandblasted, anodized or acid-etched surface, an SLA surface and hydrophilic modified surfaces each give different surface characteristics, different surface topographies, surface morphology and surface chemistry. Implants with a sandblasted and acid etched surface are moderately rough, and a systematic review found moderately rough surfaces gave stronger bone responses than smoother or rougher ones in some studies. Wettability is part of that picture. Rupp and colleagues measured 139.9° on an SLA surface and 0° on the same surface after chemical modification, and later work found new titanium surfaces at 0° became hydrophobic, around 90°, as they aged, with lasting losses in biological capability. Long term implant survival is high, about 96% at ten years in one systematic review of osseointegrated dental implants, so implant failure and implant loss are uncommon and much surface research focuses on early healing, implant stability and how soon implant loading can begin. The difficulty is measurement. Readings depend on roughness, storage age, read time and method; in one study of commercial oral implant surfaces, first advancing angles ranged from 0° to 138°, and initially hydrophobic implants became hydrophilic during repeated immersion. Without a locked method, surface wettability results cannot be compared between lots, implant types or papers.

Contact angles for the same implant system differ between labs or papers.
Lots made the same way read very differently.
Implants read more hydrophobic after weeks in storage.
A cleaning or decontamination step changes the surface more than expected.
Readings drift as the drop spreads into the rough surface.
Troubleshooting

Why implant contact angle results mislead and what to do

Why:

  • Titanium surfaces pick up carbon from air and packaging, and become less wettable over weeks.

How to detect:

  • The angle rises with storage age on the same implant type.

Corrective action:

  • Record storage age with every value, test retained samples over shelf life, and compare like with like.

Why:

  • Rough surfaces amplify wetting either way; Rupp and colleagues described roughness induced hydrophobicity on SLA.

How to detect:

  • Rough surface implants with similar chemistry read very differently on different topographies.

Corrective action:

  • Measure average surface roughness alongside contact angle and report both.

Why:

Static and dynamic methods can disagree; in one study, initially hydrophobic implants became hydrophilic over repeated immersion. Our captive bubble method entry covers wet measurement.

How to detect:

  • Your values do not match published ones for the same surface.

Corrective action:

  • Lock one method and read time, and compare only within it.

Why:

  • Residues from blasting media, etching or handling cause surface alterations that change the surface chemistry.

How to detect:

  • One lot reads lower or higher than its reference.

Corrective action:

  • Check cleaning and rinsing, and confirm with XPS or EDS on outlier lots.

Why:

  • Implant threads and small diameters distort the drop and the baseline.

How to detect:

  • Large spread between spots on one implant.

Corrective action:

  • Use flat witness coupons processed with the lot, or a flat area such as the implant shoulder.

Why:

Drop volume, read time and liquid purity change readings. Our guide to reproducible contact angle measurement covers fair comparisons.

How to detect:

  • A reference coupon reads differently between sessions.

Corrective action:

  • Write the method down and measure a reference coupon every session.

Not sure how to measure your implant surfaces?

Send treated coupons or implants, and we will compare methods on a call.

Book a 15 minute demo
Lab records

What an implant surface record contains

Each check produces a record you can file with the lot or study record. It can feed into your existing quality records and design history file.

Lot and implant

Implant system, implant material, surface treatment, lot and whether a coupon or implant was measured.

Storage and timing

Date of treatment, packaging, storage age and time out of the package before measurement.

Method settings

Liquid, drop volume, read time, static or dynamic angle, and spots measured.

Readings

Angle at each spot, the median and spread, and the differences in surface wetting against the reference.

Decision

Release, hold for investigation, or reclean, linked to other surface analysis.

Drop images

Automatic edge and baseline detection gives the same reading from the same image, so a reviewer can recheck any result.

Measurements

What to measure on the implant surface

Lot check

Water contact angle at a fixed read time

Why it matters: It shows whether the surface treatment and cleaning gave the surface of the implant you validated.

How to interpret: Compare with your reference lot measured the same way; published values for SLA and modified surfaces differ by method.

When it is not enough: It does not show roughness or composition.

Ageing

Water angle against storage age

Why it matters: Titanium surfaces lose wettability over weeks.

How to interpret: Plot angle against age for retained samples and check it stays inside your validated range.

When it is not enough: It does not prove the biological effect of ageing.

Hysteresis

Advancing and receding angles

Why it matters: Rough implant surfaces pin drops, so one static angle hides much.

How to interpret: Report both, and compare only within the same method.

When it is not enough: They do not separate roughness from chemistry.

Energy

Surface energy from two or three liquids

Why it matters: It separates polar and dispersive parts after a modification of implant surface chemistry.

How to interpret: Use one model and liquid set for all implant types you compare.

When it is not enough: Values from different models are not interchangeable.

Validation

Validated measurement approach for implant surfaces

How the Dropometer itself has been validated, and where researchers studying surface modifications of dental implants have published with it.

Peer reviewed method

The Dropometer drop shape method is published in Review of Scientific Instruments and Colloids and Surfaces A. Contact angle was validated against a KRUSS DSA100E, with a published accuracy of 0.35°.

See the validation papers

Customer evidence on titanium implant surfaces

A University of Manchester group measured SLA titanium discs before and after four cleaning brushes used to treat a failing implant, with 3 µL drops read at 5 s. Untreated discs read 84.8°; three brushes made the surface significantly more wettable, to as low as 65.3°, and one left it unchanged (Dental Materials, 2025).

Read the case study
QC Protocol

How to check implant surfaces by contact angle

Six steps for one implant type. Repeat for each new surface treatment or implant material.

1

Lock the method

Fix liquid, drop volume, read time and static or dynamic angle for each implant type.

2

Use witness coupons

Process flat coupons of the same implant material through the same surface preparation as each lot, or use a flat area of the implant.

4

Measure each lot

Measure several spots at the locked time after opening the package, and record storage age.

5

Track ageing

Measure retained samples over shelf life to confirm the surface stays in range.

We completed our gage R&R study on the unit and it performed very well.

Brandon Barbee

Corporate Quality Engineer, Zeus Industries, Polymer Manufacturing

Download the implant surface contact angle SOP

A two page SOP you can adapt for your implants, with the method lock, witness coupons, ageing checks, a troubleshooting table and a record sheet.

Contact angle measurement with the Dropometer

Contact angle measurement with the Dropometer

Example output

Example lot log for a hydrophilic titanium implant surface

Example data only. Your values and gates will differ and must come from your own validated lots.

How to read this log

Example gate: within 10° of the reference lot, measured on witness coupons at 5 s. Lot 3 read high and was held; XPS later showed extra surface carbon from a packaging change. The aged sample shows why storage age must be recorded with every value.

Example implant surface lot log

Sample Surface treatment Storage age Contact angle (°) Change vs reference (°) Result
Reference lot Blasted, etched, hydrophilic 2 weeks 18 0 Reference
Lot 1 Blasted, etched, hydrophilic 1 week 16 2 lower Release
Lot 2 Blasted, etched, hydrophilic 3 weeks 24 6 higher Release
Lot 3 Blasted, etched, hydrophilic 2 weeks 47 29 higher Hold
Retained Blasted, etched, hydrophilic 12 months 38 20 higher Review shelf life

Example data, not customer data. Grade 4 titanium witness coupons; 2 µL ultrapure water, read at 5 s, median of 5 spots.

Signal order

The order to check signals on implant surfaces

Check these in order. Each one rules out a cause before you look at the next.

1

Method and reference

Rules out drift in the measurement itself.

2

Storage age

Rules out ageing before blaming the process.

3

Lot angle

Shows whether the surface treatment ran as validated.

4

Spread across spots

Shows how uniform the treatment is across various surface regions.

FAQ

Common questions about dental implant surface wettability

Questions implant makers and researchers ask about contact angle.

It depends on the method and the surface age. Rupp and colleagues measured 139.9° on an SLA surface by a dynamic method and 0° on a chemically modified version. A Korean study measured machined titanium near 70°, anodized near 18° and blasted near 28° by sessile drop. Compare your lots with your own reference measured the same way.

Not on its own. Ferguson and colleagues found a chemically modified hydrophilic SLA surface gave better bone anchorage in early healing than SLA. Osseointegration of implant surfaces, and bone formation around the implant, also depend on roughness, chemistry, the influence of implant design and implant site. Use contact angle to record the surface, and biological studies to judge bone response.

Carbon from air and packaging builds up on the surface. Minamikawa and colleagues reported new titanium at 0° and old surfaces around 90°, citing earlier work that found surface carbon rising from under 20% to over 60% with age. Record storage age, and check retained samples over the shelf life you claim.

Sometimes. Implant threads and small diameters distort the drop, so most teams measure flat witness coupons processed with each lot, or a flat area such as the implant shoulder. For research on whole implants, dynamic methods such as Wilhelmy are used, but their values are not directly comparable with sessile drop values.

No. The FDA special controls guidance for root form dental implants asks makers to describe surface characteristics when the surface is modified, and to confirm blasting residues were removed. It does not name contact angle. Contact angle is one way to describe the surface, alongside roughness and chemistry, under ISO/TS 10993-19.

The method does. Zirconia ceramic implant, hip and knee surfaces can be measured the same way, on flat coupons or flat areas. The published values on this page are for titanium dental surfaces, so build your own reference values for other implant materials before you set gates.

Yes, as one signal. The Manchester group found three of four cleaning brushes made SLA titanium more wettable, and a plasma treatment study cut water angle from 83.1° to 24.1° on machined discs. Confirm with surface analysis before drawing biological conclusions.

Business impact

What changes when you measure implant surfaces

Typical changes in how teams work. Benchmarks are given only where a published source exists.

Before and with implant surface checks

Metric Before Dropometer With Dropometer Indicative Benchmark
Lot release Roughness and visual checks Contact angle against a validated reference No published benchmark; track on your own lots
Shelf life Assumed stable Retained samples measured over time New titanium 0° against about 90° when aged (Minamikawa et al., 2016)
Treatment comparison One published value per surface Same method on every treatment SLA 139.9° against modified SLA 0° (Rupp et al., 2006)
Long term outcome Seen years later in follow up of implants placed Surface recorded at release About 96% ten year implant survival (Howe et al., 2019)

See the measurement on your own implant surfaces

Send treated coupons or implants. We will show the comparison on a call.

Book a 15 minute demo

Estimate avoided implant lot rework

Enter your own numbers. The result is an estimate, not a Droplet Lab claim.

Implant lot rework estimate

Estimate avoided cost from implant surface lots held, reworked or rejected.

Each Dropometer unit is $5,000; the default models 1 unit.
Your own average cost to reclean, retreat or scrap one lot.
No published benchmark. Use your own lot records; start low if unsure.
Scrap cost per event from surface problems only, from your own records.

Result

~0
Monthly savings
~0
Payback period
~0
First year net benefit

Monthly savings = preventable rework cost + preventable scrap cost + other monthly savings.

Limits

What contact angle cannot tell you about an implant

Honest limits, so you know when to reach for another test.

It does not predict osseointegration on its own.
Values depend on method; sessile drop and dynamic angles differ.
Surfaces age; record storage age with every value.
Roughness changes the apparent angle.
Implant threads need coupons or a flat area.
It is not a regulatory requirement on its own.

Contact angle shows how water meets the material surface of the implant and how treatment, cleaning and ageing change it. Roughness, composition, sterility, biocompatibility and bone response need their own tests.

Book a 15 minute demo Request a quote
Related

Standards, evidence and related medical surface workflows

These pages cover the contact angle standard, the published implant research and related medical surface checks.

Standard

ASTM D7334

Advancing contact angle practice for coatings and substrates.

View use case

Case study

University of Manchester

Contact angle on SLA titanium after cleaning brushes.

View use case

Case study

University of Maryland

Contact angle on an antibacterial dental resin coating.

View use case

Published paper

Mechanical instrumentation of titanium implants

Wettability after four cleaning brushes.

View use case

Published paper

Plasma treatment of titanium surfaces

Contaminant removal and wettability on titanium discs.

View use case

Instrument

Dropometer

Contact angle and surface energy by sessile drop.

View use case

Related use case

Functional, medical and electronic coatings

All coating use cases in one place.

View use case

Related use case

Catheter hydrophilic coating validation

Hydrophilic coating checks on medical devices.

View use case

Related use case

Thin film and nanocoating characterization

Surface checks on thin films and coatings.

View use case

Guide

Medical device guide

Surface science for medical device makers.

View use case

How this page was created

Editorial and technical transparency notes for this page.

Transparency Details 4 checklist items
01

Drafting assistance

Drafted with Claude Opus 5.5 (Anthropic) using web search for sources, then edited by the Droplet Lab team.

02

Technical review

Reviewed and edited for technical accuracy by the Droplet Lab Team.

03

Verification steps

Standard identifiers, units, thresholds and key procedural claims are checked against cited sources before publication.

04

Updates

Reviewed every 12 months or when the underlying method changes.

Report a correction

Spotted an issue in this summary? Send a correction request and our team will review it.

Correction Request

We work hard to keep this page accurate and up to date. If you spot an error (wrong revision/year, missing requirement, incorrect interpretation, or broken link), tell us and we'll review it.

Contact us to report a correction
Sources

References

1.
Rupp, F., Scheideler, L., Olshanska, N., de Wild, M., Wieland, M., Geis Gerstorfer, J. Enhancing surface free energy and hydrophilicity through chemical modification of microstructured titanium implant surfaces. Journal of Biomedical Materials Research A 76A(2):323 to 334, 2006. https://doi.org/10.1002/jbm.a.30518
2.
Ferguson, S.J. et al. Biomechanical evaluation of the interfacial strength of a chemically modified sandblasted and acid etched titanium surface. Journal of Biomedical Materials Research A 78A(2):291 to 297, 2006. https://doi.org/10.1002/jbm.a.30678
3.
Minamikawa, H., Att, W., Ikeda, T., Hirota, M., Ogawa, T. Long term progressive degradation of the biological capability of titanium. Materials 9(2):102, 2016. https://doi.org/10.3390/ma9020102
4.
Att, W. et al. Time dependent degradation of titanium osteoconductivity: an implication of biological aging of implant materials. Biomaterials 30(29):5352 to 5363, 2009. https://doi.org/10.1016/j.biomaterials.2009.06.040
5.
Wennerberg, A., Albrektsson, T. Effects of titanium surface topography on bone integration: a systematic review. Clinical Oral Implants Research 20(Suppl 4):172 to 184, 2009. https://doi.org/10.1111/j.1600-0501.2009.01775.x
6.
Han, Y.S., Shin, S.W. Wettability of titanium implants depending upon surface properties. Journal of the Korean Academy of Prosthodontics 47(1):12 to 20, 2009. https://doi.org/10.4047/jkap.2009.47.1.12
7.
Rupp, F., Scheideler, L., Eichler, M., Geis Gerstorfer, J. Wetting behavior of dental implants. International Journal of Oral and Maxillofacial Implants 26(6):1256 to 1266, 2011. https://pubmed.ncbi.nlm.nih.gov/22167431/
8.
Howe, M.S., Keys, W., Richards, D. Long term (10 year) dental implant survival: a systematic review and sensitivity meta analysis. Journal of Dentistry 84:9 to 21, 2019. https://doi.org/10.1016/j.jdent.2019.03.008
9.
Alabbad, M., Silikas, N., Thomas, A. Effect of mechanical instrumentation on titanium implant surface properties. Dental Materials, 2025. See our analysis of this paper. https://dropletlab.com/validation/citations/analysis/effect-of-mechanical-instrumentation-on-titanium-implant-surface-properties/
10.
Ho, K., Shiba, T., Chen, C.Y., Kim, D.M. Plasma treatment to remove titanium surface contaminants and improve implant biocompatibility: an in vitro study. Biomimetics 10:571, 2025. See our analysis of this paper. https://dropletlab.com/validation/citations/analysis/plasma-treatment-to-remove-titanium-surface-contaminants-and-improve-implant-biocompatibility-an-in-vitro-study/
11.
Ba Armah, I. et al. Novel antibacterial resin coating for dental provisional crowns to suppress biofilms and inhibit secondary caries. Coatings 14(11):1370, 2024. See our analysis of this paper. https://dropletlab.com/validation/citations/analysis/novel-antibacterial-resin-coating-for-dental-provisional-crowns-to-suppress-biofilms-and-inhibit-secondary-caries/
12.
US FDA. Class II special controls guidance document: root form endosseous dental implants and endosseous dental implant abutments, 2004. https://www.fda.gov/medical-devices/guidance-documents-medical-devices-and-radiation-emitting-products/root-form-endosseous-dental-implants-and-endosseous-dental-abutments-class-ii-special-controls
13.
ISO/TS 10993-19:2020. Biological evaluation of medical devices, part 19: physico chemical, morphological and topographical characterization of materials. https://www.iso.org/standard/75138.html
14.
ISO 10451:2026. Dentistry: contents of a technical file for dental implant systems. https://www.iso.org/standard/83843.html
15.
ASTM D7334-08(2022). Standard practice for surface wettability of coatings, substrates and pigments by advancing contact angle measurement. See our ASTM D7334 page. https://store.astm.org/d7334-08r22.html
16.
ASTM F67-24. Standard specification for unalloyed titanium, for surgical implant applications. https://store.astm.org/f0067-24.html
17.
Chen, X. et al. Contact angle measurement with a smartphone. Review of Scientific Instruments 89(3):035117, 2018. https://pubs.aip.org/aip/rsi/article-abstract/89/3/035117/368179/Contact-angle-measurement-with-a-smartphone
18.
Surface tension measurement with a smartphone using a pendant drop. Colloids and Surfaces A: Physicochemical and Engineering Aspects. https://www.sciencedirect.com/science/article/abs/pii/S0927775717307744
19.
Droplet Lab validation papers
20.
Customer publications that cite the Dropometer
21.
University of Manchester case study
22.
University of Maryland case study