Contents
Partially compliant

ASTM D2578 standard test method for wetting tension of polyethylene and polypropylene films: the dyne test, and what contact angle adds

ASTM D2578 is the US dyne test for treated polyethylene and polypropylene film: you swab test solutions of known surface tension onto the film and find the strongest one that stays wet. The Dropometer does not run that swab test, so it gives no dyne reading. It measures wetting of the same film by water contact angle with ±0.35° accuracy, and checks your test solutions by pendant drop (Dropometer datasheet). Contact angle is an alternative method, not the test solution method the standard specifies; if a contract or customer requires an ASTM D2578 result, run a correlation study on your own samples first.

What brings you here?

Who this is for
Film extruders, converters, flexo printers and laminators who check corona or flame treated polyethylene and polypropylene film against a dyne level.
Compliance tier
Partially compliant: the Dropometer measures wetting of the same film by contact angle and checks test solutions by pendant drop. It does not run the test solution method the standard specifies.
Measurement
Water contact angle 10° to 175°, ±0.35° accuracy; pendant drop surface tension up to 75 mN/m, ±0.03 mN/m accuracy (Dropometer datasheet).
Setup
About 2 minutes. Battery powered, 1 kg, runs at the treater, at goods in or in the lab.
Last updated
October 20, 2026
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Free one page checklist for working next to ASTM D2578 on PE and PP film: check your test solutions by pendant drop, read water contact angle on the same strip, and track treatment as rolls age.

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Book a 15-minute consult about your PE or PP film

Tell us your resin, treater and the dyne level your customer asks for. We will read contact angle and your test solutions live, and tell you plainly where the Dropometer fits next to your swab test and where it does not.

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View the official standard
Gurdeep-Saini-Photo
Written 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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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.
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Verified against ASTM D2578
Gurdeep-Saini-Photo
Written By

Gurdeep Singh Saini

COO at Droplet Lab

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.

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

Evidence box: ASTM D2578 and the Dropometer

Standard

ASTM D2578-23, Standard Test Method for Wetting Tension of Polyethylene and Polypropylene Films, from ASTM International Subcommittee D20.19. ASTM states it is equivalent to ISO 8296. The method and reagents were developed for polyolefin film; on other polymers the user must show the method applies. See our ISO 8296 page.

Compliance tier

Partially compliant. The Dropometer measures wetting of the same PE or PP surface by water contact angle and surface free energy, and checks test solution surface tension by pendant drop. It does not judge whether a swabbed solution holds or breaks, so it gives no ASTM D2578 dyne value. If a contract or customer requires an ASTM D2578 result, run a correlation study on your own samples first.

Instrument performance

Contact angle range 10° to 175°, accuracy ±0.35°, display resolution 0.01°. Pendant drop surface tension up to 75 mN/m, accuracy ±0.03 mN/m, resolution 0.01 mN/m. From the Dropometer product specification.

Peer reviewed method

The drop shape method is validated against a KRUSS DSA100E in two peer reviewed papers. See our validation publications.

Customer evidence

A labels and office products manufacturer uses the Dropometer to see how inks and adhesives wet film, paper, board and plastic. Read the case study.

What it does not tell you

ASTM notes that wetting tension on its own is not a complete measure of ink, coating or adhesive adhesion. The same holds for contact angle. Keep your tape or peel test.

Executive summary

What ASTM D2578 measures on polyolefin film, where the 35 dyne note comes from and how the Dropometer fits

ASTM D2578 measures the wetting tension, or dyne level, of polyethylene and polypropylene film: you swab test solutions of known surface tension onto the film and find the strongest one that holds as a continuous film. Film extruders, converters and flexo printers in North America use it to check that corona or flame treatment lets the film retain inks, coatings and adhesives before printing, coating or laminating. ASTM states the method is equivalent to ISO 8296. The Dropometer is partially compliant. It does not run the swab test, but it measures wetting of the same film by water contact angle and surface free energy, and it checks the surface tension of your test solutions by pendant drop. Contact angle is an alternative method, not the test solution method the standard specifies; if a contract or customer requires an ASTM D2578 result, run a correlation study on your own samples first.

A dyne level in dyn/cm is the same number as mN/m. ASTM D2578 notes that 35 dyn/cm or higher has generally meant acceptable treatment for Type 1 polyethylene tubular film for commercial flexo printing, and that no general level has been set for polypropylene (source: ASTM D2578-23 summary). Many jobs ask for more: Enercon lists 38 to 44 dyn/cm for water based flexo and gravure ink on both PE and PP (source: Enercon recommended treatment ranges). In Beyond 38 Dynes: What Surface Energy Really Tells You About Adhesion, Prof Steven Abbott explains why a dyne reading signals a process change but does not on its own explain adhesion.

The Dropometer contact angle and surface energy kit reads water contact angle with ±0.35° accuracy, and surface tension by pendant drop with ±0.03 mN/m accuracy up to 75 mN/m (Dropometer datasheet). It runs on battery at the treater, as in corona treatment monitoring for print quality. For a side by side view of the two checks, see Dropometer vs dyne pens. To see why a film fails at a good dyne level, measure two liquids and work out surface free energy, as the surface energy measurement guide explains. Fowkes, van Oss Chaudhury Good and Equation of State are built into the software; OWRK is not built in, so enter your angles in the free Contact Angle to Surface Energy Calculator. Compare your results with our surface free energy reference values for common polymers.

Further reading: the plastics guide, reproducible surface energy calculation from contact angles and a classroom experiment on contact angle on treated and untreated surfaces.

How the Dropometer fits the test method for wetting tension

Checking test solutions and reading water contact angle next to your ASTM D2578 swab test, step by step

From a treated PE or PP roll to a correlation you can trend

These steps describe Dropometer measurements that sit next to the ASTM D2578 swab test. They are not the swab procedure and do not replace it. Buy the current edition and follow it for any dyne level you report.

±0.35°

Contact angle accuracy

From the Dropometer product specification. Display resolution is 0.01°.

±0.03 mN/m

Test solution check

Pendant drop surface tension accuracy up to 75 mN/m, from the Dropometer product specification.

8 h

Battery time

5 V battery operation, so the unit can sit at the treater or at goods in.

1

Check your test solutions by pendant drop

Hang a drop of each test solution from the needle and read its surface tension. Enter the solution density from the supplier's data sheet. Compare each value with the label and the tolerance your supplier states, and replace solutions that have drifted. See the surface tension measurement guide.

2

Take and mark the PE or PP specimens

Cut strips across the web width and mark the treated side. Handle them by the edges, because skin oils change both the swab result and the angle. Condition them as the standard specifies, and note the treatment date and the test date.

3

Run your ASTM D2578 swab test

Swab the test solutions on one part of each strip as the standard specifies, using a clean swab for each solution, and record the wetting tension. Suppliers describe about one square inch per swab and a two second hold (source: ACCU DYNE TEST). The Dropometer does not do this step.

4

Read the water contact angle

Lay the strip flat on the sessile stage, treated side up, on an area the solutions have not touched. Dispense a fixed drop volume of deionised water and read the angle at a fixed time. Automatic edge and baseline detection gives the same reading from the same image.

5

Add surface free energy when ink still fails

Repeat with a second liquid such as diiodomethane, then calculate surface free energy with the Fowkes, van Oss Chaudhury Good or Equation of State model in the software. For OWRK, which is not built in, enter your angles in the free Contact Angle to Surface Energy Calculator.

6

Record, trend and build your correlation

Record wetting tension, mean angle, spread, position, resin grade, treatment date, test date and room conditions. Plot angle against wetting tension and set your accept limit from that data. Report dyne levels from the swab test, not from the angle.

7

Watch the full measurement

This video shows a complete Dropometer contact angle measurement, from setup to result. It covers the steps above in one run.

Dropometer contact angle measurement, start to finish.

Validated measurement approach

Independent benchmarking and publication-based validation references.

Peer reviewed method

The Dropometer drop shape method is validated against a KRUSS DSA100E in two peer reviewed papers, one in Review of Scientific Instruments and one in Colloids and Surfaces A. Contact angle accuracy is ±0.35° (Dropometer product specification).

Read the validation papers

Customer evidence

We have no published client study run next to ASTM D2578 yet. A labels manufacturer uses the Dropometer in two labs to check how inks, adhesives and coatings wet film and other substrates.

Read the case study

Set limits for polyethylene and polypropylene films from your own correlation

ASTM D2578 · PE and PP film · 35 dyne note

ASTM D2578 tells you how to find the wetting tension. It sets no pass level for every job. Its own note gives one reference point: 35 dyn/cm or higher has generally meant acceptable treatment for Type 1 polyethylene tubular film for commercial flexo printing, and no general level exists yet for polypropylene (source: ASTM D2578-23 summary). Treater makers publish higher ranges for many inks and coatings. Enercon lists 36 to 40 dyn/cm for solvent flexo ink on PE and 38 to 40 on PP (source: Enercon recommended treatment ranges). Your customer, ink or adhesive supplier, or your own trials set the real level. For why a dyne target is a starting point, read Beyond 38 Dynes by Prof Steven Abbott.

No published table converts water contact angle into an ASTM D2578 dyne level for every PE or PP grade. Slip, antiblock and antistatic additives move both readings. To use contact angle against a dyne specification, run a correlation study: read rolls across your treatment range and storage times with your test solutions and with the Dropometer, then set your contact angle limit from that data. Repeat it when you change resin, additive package or treater settings.

Check the solutions too. Read each one by pendant drop, compare it with its labelled value and the tolerance your supplier states, and replace any that have drifted. Enercon advises dating solutions and replacing them after about six months (source: Enercon on dyne solutions and pens).

Example output

Example data for illustration only. These are not measured results. Your own film, treatment, solutions and limits decide the numbers.

Example: one corona treated BOPP roll tested to ASTM D2578 and by water contact angle as it ages in storage

Days since treatment ASTM D2578 wetting tension (dyn/cm) Mean water contact angle (°) Std dev (°) Decision (example limit 81°)
04470.60.9Accept
34273.91.0Accept
74077.20.8Accept
143880.31.1Accept, close to limit: use soon
283683.81.2Hold: below the 38 dyn/cm minimum
563486.91.3Hold: retreat or return

How to read this table

Each row is one test day on the same example roll. The wetting tension is the operator's ASTM D2578 swab reading. The water contact angle is the mean of five drops on the Dropometer at the same reading time. The example customer minimum is 38 dyn/cm. The example contact angle limit of 81° or lower was set from this correlation, because the 38 dyn/cm reading came at 80.3°.

Example output chart

The same example data as the table: water contact angle on one BOPP roll as it ages, with the example limit set from the ASTM D2578 correlation.

Line chart of example water contact angle on one corona treated BOPP roll rising from 70.6 to 86.9 degrees over 56 days of storage, with an example limit at 81 degrees that matches a 38 dyn/cm ASTM D2578 reading

Example data, not measured results.

Business impact

What changes when a measured angle sits next to your test solutions

Metric Before Dropometer With Dropometer Results
How the check is read Swabbed solution judged by eye as holding or breaking Water contact angle read from the drop image No published benchmark
Result format The highest solution that holds, in solution steps An angle per drop, 0.01° display resolution, ±0.35° accuracy Dropometer product specification
Operator spread About 1.0 dyn/cm between operators, 0.5 dyn/cm for a good inspector Automatic edge and baseline detection: same reading from the same image Swab figures: ACCU DYNE TEST. Angle: no published benchmark
Test solution check Replace solutions on a fixed date Pendant drop reading of each solution, ±0.03 mN/m accuracy up to 75 mN/m Dropometer product specification
Reported ASTM D2578 dyne level Test solutions Still test solutions ASTM D2578 scope

See the measurement on your own film

Bring a fresh roll, an aged roll and your test solutions. We will measure all of them live.

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ROI estimate

Estimate the cost of the treatment failures this check can catch

Enter your own numbers. The defaults are examples, not Droplet Lab results.

Quality cost snapshot

Estimate what wetting related failures cost you.

Example only. Use what you see in a trial on your own samples.
Your own figure.
Your own estimate.

Result

~0
Estimated annual cost today
~0
Estimated annual cost avoided
~0
Payback period

Annual exposure combines audit/CAPA cost, customer rejections, and recall probability; avoided exposure applies the risk reduction percentage.

Method settings next to the standard test method for wetting tension

Lock these before you compare contact angle with ASTM D2578 readings between shifts, lines or sites

Parameter Recommended Setting Technical Rationale
Reported dyne level From the ASTM D2578 swab test only Contact angle is an alternative method, not the test solution method the standard specifies.
Film type Polyethylene or polypropylene The method and reagents were developed for these polyolefins. Other polymers need their own check, or see ISO 8296.
Test liquid for the angle Deionised water Water contact angle is the usual partner check for treated film, as in ASTM D5946.
Drop volume and reading time Fixed for every drop Changing either adds spread that is not about treatment.
Fit model Young-Laplace or polynomial, the same for every run Both models are in the Dropometer software. Do not mix them within one study.
Test solution check Pendant drop, solution density entered, read soon after the drop forms Solutions drift with age and swab contamination, and solvent can evaporate from the drop.
Storage time Record treatment date and test date for every reading Treatment fades in stored rolls, so a reading without dates cannot be compared.
Environment Condition as the standard specifies; record room temperature and humidity The Dropometer has no temperature or humidity control and runs at 10 to 45 °C.

Is ASTM D2578 the right test?

Pick the method by the question you need answered

Start: What do you need to know about the treated PE or PP film?

A dyne level your customer specifies

Signals:

Your purchase order or specification asks for a minimum wetting tension on PE or PP film measured to ASTM D2578.

Rule-out:

Use ASTM D2578 test solutions. The Dropometer does not run the swab test. It can check your solutions by pendant drop, and contact angle can sit beside the swab result once you have a correlation study on your own film.

Treatment fading in stored rolls

Signals:

Rolls pass at the extruder but print poorly weeks later, and you want a number to trend by storage time.

Rule-out:

Trend water contact angle to ASTM D5946 / ISO 15989 by treatment date. The Dropometer is fully compliant with that method.

Are my test solutions still on value?

Signals:

Your solutions are old, have been swabbed many times, or give readings that disagree between operators.

Rule-out:

Read each solution by pendant drop on the Dropometer, up to 75 mN/m with ±0.03 mN/m accuracy, and compare with the label.

Film that is not PE or PP

Signals:

You treat PET, PVC, polyamide or another plastic film or sheet.

Rule-out:

ASTM D2578 was developed for polyolefins. See ISO 8296, which covers plastic film and sheeting, and check your correlation on that material.

Decision tree at a glance

Start from the question you need answered. Blue boxes are measurements the Dropometer runs.

Decision tree for choosing between ASTM D2578 test solutions, a water contact angle trend to ASTM D5946, a pendant drop check of test solutions and ISO 8296 for films other than polyethylene and polypropylene

Is ASTM D2578 the right test?

Interpreting the wetting tension of polyethylene and polypropylene

What a wetting tension and a contact angle tell you on polyolefin film, and what they do not

Higher wetting tension, lower angle: On one PE or PP grade, stronger treatment raises the swab reading and lowers the water contact angle. Your correlation shows how far each moves.
Same physics, different reading: ASTM explains that at a 0° contact angle the film's wetting tension equals the liquid's surface tension. The swab test finds that point by eye; the Dropometer reads angles from 10° up.
Treatment fades with storage: Record treatment date and test date. A roll tested weeks later can read a lower dyne level and a higher angle.
Neither proves adhesion: ASTM notes that wetting tension alone is not a complete measure of adhesion. Contact angle has the same limit.
Expert perspective

Why a swab reading and a contact angle describe the same PE or PP surface

On a real surface, the receding angle from a sessile drop and from a tilted plate can disagree wildly: one method is not a substitute for the other. The application decides.

Dr. Alidad Amirfazli

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

Common pitfalls and limits

Honest limits of the method and of the Dropometer

The Dropometer gives no ASTM D2578 dyne value. Relate contact angle to dyne level only through your own correlation study; no published table converts one into the other.
Slip, antiblock and antistatic additives can bloom to the surface over time and change both the swab result and the angle.
Test solutions drift with age and swab contamination. Check them by pendant drop and replace any that have moved.
The formamide and 2-ethoxyethanol solutions are hazardous. Follow the supplier's safety data sheet when you swab or hang drops.
The Dropometer has no temperature or humidity control. Condition samples and solutions, and record room conditions (operating 10 to 45 °C).
The camera runs at 10 frames per second. That suits a reading at a fixed time, not millisecond spreading studies.
FAQ

Frequently asked questions

What does ASTM D2578 measure?

It measures the wetting tension, or dyne level, of polyethylene and polypropylene film. You swab a series of test solutions of known surface tension onto the treated surface and find the strongest one that holds as a continuous film rather than pulling into droplets. The method and reagents were developed for polyolefins, so on other polymers you must show it applies.

What dyne level does ASTM D2578 call acceptable?

The standard sets no pass level for every job. A note says 35 dyn/cm or higher has generally meant acceptable treatment for Type 1 polyethylene tubular film for commercial flexo printing, and that no general level exists yet for polypropylene (source: ASTM D2578-23 summary). Many inks need more: Enercon lists 38 to 44 dyn/cm for water based flexo on PE and PP. Set your level from film that printed and laminated well, and read Beyond 38 Dynes by Prof Steven Abbott for why a dyne target is a starting point.

Can the Dropometer run ASTM D2578?

Not the swab test itself, so it is partially compliant. It measures wetting of the same PE or PP film by water contact angle and surface free energy, and it checks your test solutions by pendant drop. Contact angle is an alternative method, not the test solution method the standard specifies; if a contract or customer requires an ASTM D2578 result, run a correlation study on your own samples first.

Is ASTM D2578 the same as ISO 8296?

ASTM states that D2578 is equivalent to ISO 8296. ASTM D2578 is written for polyethylene and polypropylene film, while ISO 8296 covers plastic film and sheeting more broadly. Quote the designation your customer names in the specification. See our ISO 8296 page.

Can I convert a water contact angle into an ASTM D2578 dyne level?

Not with a general table. The link between angle and dyne level depends on your resin, additives, treatment and storage time. Read the same rolls with your test solutions and with the Dropometer, plot one against the other, and set your contact angle limit from that data. Keep reporting the dyne level from the swab test.

Can the Dropometer check my dyne test solutions?

Yes. It reads surface tension by pendant drop up to 75 mN/m with ±0.03 mN/m accuracy (Dropometer datasheet), which covers the usual solution range. Enter each solution's density, read it soon after the drop forms, and compare it with the label and the tolerance your supplier states.

Why do swab results differ between operators?

The swab test is read by eye, so pressure, swab loading and judgment of the hold time all matter. ACCU DYNE TEST reports that a good inspector repeats within about 0.5 dyn/cm and that results between operators usually agree within about 1.0 dyn/cm (source: ACCU DYNE TEST). Train all testers the same way, and use a measured contact angle to trend between solution steps.

Harvard University
Eli Lilly
Zeus
DuPont
Essilor Luxottica
Raytheon
Cornell University
P&G
Axiom Space
Lululemon
Holcim
CNRS France
FLIR
Avery Dennison
US DOE
BRP
Heraeus
Singapore Institute of Technology
East China University
Indian Institute of Science
NRC Canada

Legal note

This page summarises ASTM D2578 in our own words and does not reproduce the standard. Buy the current edition from ASTM before you write a procedure. The Dropometer is partially compliant: it measures wetting of the film by contact angle and checks test solutions by pendant drop, but it does not run the test solution method the standard specifies. Droplet Lab does not certify compliance. Your own method validation does.

View the official standard Book a 15-minute consult

How this page was created

Sources, review and tools

Transparency 4 checklist items
01

Sources

ASTM D2578-23 listing; ANSI webstore: ASTM D2578-23; Nimonik: ASTM D2578-23 summary; Enercon: ASTM cotton swab dyne testing, the Dropometer product specification and Droplet Lab validation papers.

02

Drafting assistance

Drafted with Claude (Anthropic) from the sources listed, then reviewed by Droplet Lab.

03

What we did not do

We did not copy text from the standard. Buy the current edition for the full procedure.

04

Last checked

October 2026

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References

1. ASTM D2578-23. store.astm.org/d2578-23.html
2. ANSI webstore: ASTM D2578-23. webstore.ansi.org/standards/astm/astmd257823
3. Nimonik: ASTM D2578-23 summary. standards.nimonik.com/products/astm/d2578/
4. Enercon: ASTM cotton swab dyne testing. enerconind.com/web-treating/library-resource/astm-cotton-swab-dyne-tes
5. Droplet Lab. Peer reviewed validation papers in Review of Scientific Instruments and Colloids and Surfaces A. dropletlab.com/validation/publications/
6. Droplet Lab. Dropometer product specification, 2026. dropletlab.com/products/dropometer/