Contents

Electrical & Electronics Industry
The Practical Guide to Surface Science (2026)

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Written by
Dr Amit Pratap Singh
PhD, Delhi University Post Doc - AIST Japan
Guest Author
Read More
alidad
Reviewed by
Dr Alidad Amirfazli
Dr. Amirfazli, a leading expert in surface wetting and superhydrophobic coatings, has 250+ publications, edits Advances in Colloid and Interface Science, and has received multiple research awards.
Scientific Advisor & Co-founder
Read More
D54c15105cfe94f786c500e4091d6ea65457608fde49ba183c8f862814a54249?s=100&d=m
Written By

Dr Amit Pratap Singh

Guest Author

PhD, Delhi University

Post Doc - AIST Japan

alidad
Reviewed By

Dr Alidad Amirfazli

Scientific Advisor & Co-founder

Dr. Amirfazli, a leading expert in surface wetting and superhydrophobic coatings, has 250+ publications, edits Advances in Colloid and Interface Science, and has received multiple research awards.

Featured Studies & Publications

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

This is a practical guide to Surface Science for researchers working in the Electrical & Electronics Industry.

In this all-new guide you’ll learn all about:

  • Crucial surface science principles
  • The significance of surface science measurements for the Electrical & Electronics industry
  • Applicable ASTM Standards & Guidelines

Let’s dive right in.

Electrical & Electronics

Contents

measurement

Contact Angle Measurement

tension

Surface Tension Measurement

energy

Surface Energy Measurement

sliding angle

Sliding Angle Measurement

realworld

Real World Applications

standardand guide

Standards and Guidelines

Executive Summary

What it covers: How electronics and electrical teams use contact angle, surface free energy, surface and interfacial tension on boards, printed electrodes, insulators, battery materials and oils. Each measurement is tied to a real problem, a standard and published client work.
Key insights: A Clemson study found that 36 laser inscribed graphene electrodes made in one day varied in contact angle by more than 30 percent. Splitting production into batches of nine with laser downtime cut that to under 5 percent. Contact angle checks the surface before soldering or coating; it does not replace the solder or adhesion test itself.
Business value: A contact angle check after plasma, cleaning or plating catches a bad surface before coating, bonding or assembly. One portable kit also works with no network connection after a one time licence activation, which suits restricted sites.
Standards to follow: IEC TS 62073 describes contact angle methods for the wettability of insulator surfaces, and ASTM D7490 describes surface free energy of coatings from contact angles. IPC J-STD-003 tests solder wetting on boards with molten solder, which the Dropometer does not measure.
Bottom line: Use contact angle to check surfaces before solder mask, conformal coating or bonding, and interfacial tension to trend insulating oil condition. Start with your most common failure, then book a 15 minute demo to try it on your own parts.

Chapter 1: Introduction

In electronics, many field failures start at a surface or an interface. A conformal coating that does not wet a board pulls back from edges and leaves parts exposed. A battery separator that wets slowly holds up electrolyte filling.

These are the places where wetting decides yield in electronics work:

The Dropometer contact angle and interfacial tension kit measures contact angle, surface and interfacial tension, surface free energy and sliding angle with one portable setup. Its method was validated against a KRUSS DSA100E in two peer reviewed papers. If you are new to the terms, start with wettability.

We use the following surface properties to understand the behavior of Electrical & Electronics products and improve their quality.

Chapter 2: Contact Angle Measurement

The contact angle quantifies the wettability of a surface by representing the angle between a liquid’s surface and a solid surface.
Dropletlab Research

Sample Image taken from Droplet Lab Tensiometer.

Young – Laplace Method

  • 1. This method uses the whole drop profile to calculate the contact angle value.
  • 2. This method is only compatible with an axisymmetric drop, which is not always seen in practice because a needle is typically inserted into the drop to increase or decrease the drop volume.
  • 3. This method yields more consistent results than the polynomial fitting method.

Polynomial Method

  • 1. This method uses only a portion of the drop profile to calculate the contact angle value.
  • 2. This method is compatible with both axisymmetric and non-axisymmetric drops.
  • 3. The measurement results of this method are less consistent, as they can be influenced by local surface imperfections.
Dynamic Contact Angle

Ideally, when we place a drop on a solid surface, a unique angle exists between the liquid and the solid surface. We can calculate the value of this ideal contact angle (the so-called Young’s contact angle) using Young’s equation. In practice, due to surface geometry, roughness, heterogeneity, contamination, and deformation, the contact angle value on a surface is not necessarily a single consistent value but rather falls within a range. The upper and lower limits of this range are known as the advancing and receding contact angles, respectively. The values of advancing and receding contact angles for a solid surface are highly sensitive to many parameters, such as temperature, humidity, homogeneity, and minor contamination of the surface and liquid. For example, the advancing and receding contact angles of a surface can differ at different locations.

Dynamic Contact Angle versus Static Contact Angle

Practical surfaces and coatings naturally show contact angle hysteresis, indicating a range of equilibrium values. When we measure static contact angles, we get a single value within this range. Solely relying on static measurements poses problems, like poor repeatability and incomplete surface assessment regarding adhesion, cleanliness, roughness, and homogeneity.

In practical applications, we need to understand how easily a liquid spreads (advancing angle) and how easily it is removed (receding angle), such as in painting and cleaning. Measuring advancing and receding angles offers a holistic view of liquid-solid interaction, unlike static measurements, which yield an arbitrary value within the range.

This insight is crucial for real-world surfaces with variations, roughness, and dynamics, aiding industries like cosmetics, materials science, and biotechnology in designing effective surfaces and optimizing processes.

Learn how Contact Angle measurement is done on our Tensiometer

For a more complete understanding of Contact Angle measurement, read our Contact Angle measurement: The Definitive Guide

Contact Angle measurement: The Definitive Guide

Open Benchmark Data: Contact Angle & Surface Energy

These reference measurements show how deionized water wets four standard substrates measured with the Droplet Lab Dropometer. Use them as visual and numerical benchmarks when you're checking your own sample preparation, treatments, and chemistry.

Full contact angle and surface energy datasets (including additional liquids and statistics) are available on our dataset hub.

Glass - DI Water
Glass - DI Water
Nylon - DI Water
Nylon - DI Water
PMMA - DI Water
PMMA - DI Water
Teflon - DI Water
Teflon - DI Water

The droplet images above are taken from the same benchmark series as our open dataset. For each substrate and probe liquid we report:

● Advancing and receding contact angles (and hysteresis)
● Derived surface energy (SFE) values based on multi-liquid measurements
● Measurement conditions, uncertainties, and sample preparation details

Comparing your own droplet shapes and angles against these references is a fast way to spot contamination, treatment drift, or unexpected changes in wettability.

Explore the full benchmark datasets (contact angle + surface energy)

Measurements were performed with the Droplet Lab Dropometer under controlled laboratory conditions. Treat these values as sanity checks and starting points for your own process targets, not as product specifications.

Chapter 3: Surface Tension Measurement

This property measures the force that acts on the surface of a liquid, aiming to minimize its surface area.

Surface Tension Measurement

Sample Image taken from Droplet Lab Tensiometer

Dynamic Surface Tension

Dynamic surface tension differs from static surface tension, which refers to the surface energy per unit area (or force acting per unit length along the edge of a liquid surface).

Static surface tension characterizes the equilibrium state of the liquid interface, while dynamic surface tension accounts for the kinetics of changes at the interface. These changes could involve the presence of surfactants, additives, or variations in temperature, pressure, and composition at the interface.

When to use Dynamic Surface Tension Measurement

Dynamic surface tension is essential for processes that involve rapid changes at the liquid-gas or liquid-liquid interface, such as droplet and bubble formation, coalescence (change in surface area), the behavior of foams, and the drying of paints (change in composition, e.g., evaporation of solvent). It is measured by analyzing the shape of a hanging droplet over time.

Dynamic surface tension applies to various industries, including cosmetics, coatings, pharmaceuticals, paint, food and beverage, and industrial processes, where understanding and controlling the behavior of liquid interfaces is essential for product quality and process efficiency.

Learn how Surface Tension measurement is done on our Tensiometer

For a more complete understanding of Surface Energy measurement, read our Surface Tension measurement: The Definitive Guide

Surface Tension measurement: The Definitive Guide

Chapter 4: Surface Energy Measurement

Surface energy refers to the energy required to create a unit area of a new surface.
231

Sample Image taken from Droplet Lab Tensiometer

Learn how Surface Energy measurement is done on our Tensiometer

For a more complete understanding of Surface Energy measurement, read our Surface Energy measurement: The Definitive Guide

Surface Energy measurement: The Definitive Guide

For benchmark contact angle and surface energy values on glass, nylon, PMMA, and Teflon, see the Open Benchmark Data panel above or visit our Dataset Hub for full CSV downloads.

Dataset Hub

Chapter 5: Sliding Angle Measurement

The sliding angle measures the angle at which a liquid film slides over a solid surface. It is commonly employed to assess the slip resistance of a surface.

sliding angle 1

Sample Image taken from Droplet Lab Tensiometer

Learn how Sliding Angle measurement is done on our Tensiometer

For a more complete understanding of Sliding Angle measurement, read our Sliding Angle Measurement: The Definitive Guide

Sliding Angle Measurement: The Definitive Guide

Chapter 6: Real-World Applications

Within the Electrical & Electronics industry, several case studies exemplify the advantages of conducting surface property measurements.

Batch-to-Batch Variation in Laser-Inscribed Graphene (LIG) Electrodes for Electrochemical Sensing

The study evaluates batch-to-batch variability when manufacturing arrays of LIG electrodes on polyimide using a CO₂ laser, then characterizes the material using goniometry, stereomicroscopy, open-circuit potentiometry, and cyclic voltammetry. It reports that bare LIG can show low variability under controlled fabrication/testing conditions, but Pt metallization (nanoplatinum electrodeposition) substantially boosts electrochemical response while increasing batch variability, creating a key performance vs. manufacturability tradeoff for scaling sensor production.

Role of the Droplet Lab Goniometer

The Droplet Lab DROPOMETER‑M was used as a wettability/quality-control screen for LIG electrode surfaces by measuring static contact angle using a 2 µL sessile droplet placed on the LIG working area (Section 2.4). Because the LIG surface produced large fitting errors with axisymmetric Young-Laplace methods, the authors used a non-axisymmetric polynomial method for contact-angle calculation and archived the images (Section 2.4).

In the Electrical & Electronics context, this is significant because contact angle provides a fast, non-destructive indicator of surface state and process consistency for laser-processed carbon electrodes, helping teams detect when manufacturing conditions (e.g., long print runs, laser downtime/maintenance) begin to degrade uniformity (Section 3.1; Figure 1).

Where the paper explicitly ties wettability to liquid/surface-tension behavior:
In Section 3.1, the authors note that common buffers (HEPES, MES, Tris) lower contact angle versus DI water and interpret this as surfactant-like behavior impacting interfacial conditions; however, surface tension is not directly measured.

Key Findings

  • Bare LIG wettability is consistent under controlled batching: In DI water, LIG showed a mean contact angle of ~58.6° (hydrophilic) with <5% within-batch variation when fabricated in smaller batches (Section 3.1; Figure 1D).
  • Long production runs can break wettability consistency: A single-day run of 36 electrodes caused >30% contact-angle variation; splitting production into four batches of nine with laser downtime reduced variation to <5% (Section 3.1).
  • Electrolyte/buffer choice changes wetting behavior: HEPES, MES, and Tris reduced contact angle compared with DI, consistent with surfactant-like effects that can alter the electrode-electrolyte interface during electronics-grade sensor testing (Section 3.1; Figure 1B).
  • Metallization shifts surface wetting: After nanoplatinum deposition, contact angle increased to ~78° (more hydrophobic), indicating a meaningful surface-property change relevant to fluid handling and sensor interface design (Section 3.1; Figure 1C/E).
  • Electrochemical conditioning requirements differ by configuration: Peak oxidative current stabilized after ~4 CV scans for single LIG electrodes vs ~2 scans for the LIG sensor-chip format (Section 3.2; Figure 2).

Performance vs repeatability tradeoff is real for scaling: Pt metallization increased peak current/capacitance proxies but batch variation increased substantially (discussion around Sections 3.3-3.4; Figure 5C), emphasizing the need for QC gates before high-volume electronics production.

Why It Matters

For manufacturers scaling printed/flexible electrochemical sensors or other LIG-enabled microelectronic components, contact angle is a practical incoming/inline QC metric: it quickly flags changes in surface condition that can affect electrolyte wetting, interfacial stability, and ultimately device-to-device variability. This paper shows that process controls (batch sizing, laser downtime/maintenance) can dramatically improve wettability consistency, and that metallization methods should be selected with an explicit tradeoff mindset, balancing improved electrochemical performance against increased batch variability that complicates production specs and yields.

Method Snapshot

  • Sample: CO₂-laser-inscribed graphene electrodes on polyimide film (with and without nanoplatinum metallization).
  • Droplet / temperature / angle type: 2 µL sessile droplets at room temperature; static contact angle computed using a non-axisymmetric polynomial fit (Droplet Lab DROPOMETER‑M; Section 2.4).

Surface tension: Not directly measured; buffer-dependent wetting changes are discussed as surfactant-like effects (Section 3.1).

Data Note

Hydrophobicity study of LIG and nPt-LIG. (A) Representative images from goniometry testing of four electrode batches (LIG sample with 2 μL DI). Results of non-axisymmetric method and calculated contact angle shown on each image. Violin plots show contact angle in testing liquids for: (B) non-modified LIG electrodes, and (C) nPt-LIG electrodes. White dots represent median value, black boxes show range from the lower to the upper quartile, whiskers present the variability outside upper and lower quantile, and the shape of violin indicates the data density (n = 24 for each group). Average contact angle is shown for: (D) non-modified LIG, and (E) nPt-LIG electrodes.

Figure

Citation (APA Format)

Tang, Y., Moreira, G. A., Vanegas, D., Datta, S. P. A., & McLamore, E. S. (2024). Batch-to-batch variation in laser-inscribed graphene (LIG) electrodes for electrochemical sensing. Micromachines, 15, 874. doi:10.3390/mi15070874

View Publication →

Solder mask adhesion on printed circuit boards

Solder mask and conformal coatings bond well only when the board surface is clean and wettable. Water contact angle on a coupon after cleaning or plasma shows whether the surface is ready.

IPC J-STD-003 tests whether pads and holes wet with molten solder, which the Dropometer does not measure. It adds room temperature checks before soldering, such as flux surface tension and finish contact angle. IPC TM-650 cleanliness tests are not contact angle tests either, so use contact angle alongside them. See plated coating wettability for finishes.

Solder mask adhesion on printed circuit boards

Wettability of solar cell surfaces

Solar panels lose output when cover glass and films collect dirt and water films. Contact angle shows whether a cover surface is clean, and whether an anti soiling or water shedding coating is working.

ASTM C813 describes contact angle for hydrophobic contamination on glass, and ASTM F22 and ASTM F21 cover hydrophobic surface films. For polymer films and encapsulants, ASTM D7490 works out surface free energy from contact angles of two or more probe liquids. Our surface energy calculator runs the calculation.

Wettability of solar cell surfaces

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Chapter 7: Standards and Guidelines

In an industry where precision reigns supreme, how can Electrical & Electronics manufacturers ensure their products withstand scrutiny? The answer lies in standards and guidelines: the compass that guides them through the complex maze of quality and performance.

IPC J-STD-003, Solderability Tests for Printed Boards (Wetting Balance Companion)

What it is

IPC J-STD-003 defines test methods used to assess solderability (acceptable wettability) of printed wiring board conductors/lands/PTHs, helping confirm fabrication, storage, and handling have not degraded solderability. This companion workflow adds a non-destructive, pre-solder screening layer using water contact angle (WCA) and optional surface free energy (SFE) trending to detect contamination/handling drift before destructive solderability testing or assembly builds.

When to use it

Incoming / pre-assembly pad readiness screening

Use WCA (and optional SFE trend) to flag lots/panels with elevated contamination risk before committing to destructive J-STD-003 testing or production assembly.

Failure triage when solderability or assembly defects drift

Use mapped WCA/SFE patterns (median + variability) to separate likely causes such as handling residue, storage aging, finish-process drift, or measurement artifacts.

In-scope / Out-of-scope

In scope
  • Non-destructive wettability / cleanliness trending on PCB finishes (e.g., Cu, ENIG/ENEPIG, immersion Sn/Ag) via WCA mapping at a fixed timestamp.
  • Optional SFE “trend mode” (comparative, fixed protocol) to improve discrimination when WCA alone is not sufficient.
  • Correlation (“calibration”) to your chosen J-STD-003 method outcome (e.g., wetting balance / other listed methods) or to downstream defect rates to create defensible internal gates.
  • Routine controls and drift monitoring using a known-good “golden coupon” and an intentionally aged/handled sentinel coupon.
Out of scope
  • Replacing J-STD-003 solderability tests (WCA/SFE does not generate wetting balance force-time curves or molten-solder solderability outcomes).
  • Molten solder contact-angle measurement at reflow/immersion temperatures when the instrument operating environment is limited to ≤45 °C (room-temperature screening only).
  • Universal accept/reject cutoffs for WCA/SFE (thresholds must be derived from your correlation dataset and process window).
  • Claims of assembly success or design validation based solely on WCA/SFE (surface readiness ≠ guaranteed process robustness).

Minimum you must report (checklist)

  • Standard referenced (IPC J-STD-003 revision used) and the J-STD-003 method you correlate against (e.g., wetting balance or other method used in your program).
  • Feature + finish definition (pad type/geometry, finish stack, lot/date code, time since finish, storage/packaging/handling notes).
  • Instrument + mode (WCA only, or WCA + SFE trend) and contact-angle type (static at fixed timestamp; optional advancing/receding if used).
  • Probe liquid(s) (DI water for baseline; list SFE liquid set if used) and droplet volume (fixed; small enough to remain fully on-pad).
  • Timepoint definition (e.g., WCA @ 2.0 s ± 0.2 s) and capture/fit criteria used by the software.
  • Sampling plan (number of spots, mapped locations across coupon/panel; report median + IQR or equivalent variability metric).
  • Environment (temperature/RH) and any cleaning/handling controls (gloves, no silicone wipes, time from unpack to test).
  • Controls + gates (golden coupon results per run/shift, drift sentinel, and your Green/Yellow/Red thresholds tied to correlated outcomes; include how you handle “≤10° instrument floor” reporting).

Note: Contact angle/SFE screening is a companion tool that provides a fast, localized “surface readiness” signal; it does not certify IPC compliance or replace molten-solder solderability tests. Because the instrument is limited to room-temperature operating conditions, treat any flux/spread measurements as comparative screening only, not a soldering-temperature wetting metric.

How to interpret results (guardrails)

  • Directionality, not absolutes: At a fixed timestamp, lower WCA generally indicates a cleaner, higher-energy surface (lower organic contamination risk), but only your correlation dataset makes it a QC gate.
  • Trend + variability matter: A rising median WCA and/or rising IQR (non-uniformity) is an early warning for handling residue, storage aging, or inconsistent processing across zones.
  • SFE is comparative: If you use SFE, interpret it as a controlled trend vs a reference coupon, not as an absolute material constant (keep liquid set, volume, and timepoint fixed).
  • Don’t overclaim measurement limits: If the surface fully wets below the device range, record “≤10° (instrument floor)”; reject/re-run spots with off-pad placement, poor fit/QC, or visible residue at the site.
Read our IPC J-STD-003 page View the official IPC J‑STD‑003 Standard

Now It’s Your Turn

We hope this guide showed you how to apply surface science in the Electrical & Electronics industry.

Now we’d like to turn it over to you: 

  • What’s the #1 real-world application from this post that you want to try first?
  • Perhaps we missed a relevant industry standard.
  • Or maybe you have a question about something you read.

Feel free to leave a comment below—we’d love to hear from you.

Frequently asked questions

Which surface measurement should an electronics lab start with?

Start with the failure you see most. Use water contact angle to check boards, finishes and parts after cleaning, plasma or plating. Use surface free energy from two or more probe liquids when coatings or adhesives must bond. Use surface tension for fluxes, inks and electrolytes, and interfacial tension for insulating oils. Our contact angle guide explains the method.

Which standards apply to contact angle in electronics and electrical work?

IEC TS 62073 describes contact angle methods for insulator wettability, and IEC TR 62039 covers hydrophobicity of polymeric insulators. ASTM D7490 covers surface free energy of coatings, and IPC J-STD-003 covers solder wetting. The Dropometer uses the sessile drop and pendant drop methods, so check which method your specification names.

Can contact angle replace a solderability test?

No. Only the J-STD-003 test shows whether molten solder will wet a pad or fill a hole. The Dropometer works at room temperature, so it checks the finish and the flux before soldering. Any link between those readings and solder results must come from your own correlation study. See PCB surface prep.

Can I measure contact angle on rough printed or laser made electrodes?

Yes, with the right fit. The Clemson McLamore lab found symmetric Young Laplace fitting failed on rough graphene, so it used a polynomial fit with 2 microlitre drops. Its batch to batch variation study used contact angle to track electrode consistency. See LIG electrode QC.

Can the Dropometer measure battery electrolytes and corrosive liquids?

Yes, with wetted parts the liquid will not attack. A North American battery R&D team set up contact angle, surface tension and surface energy for electrolytes, some of which attack metal. Plastic needles were recommended. A UK thermoelectric company uses contact angle and surface tension on one unit. See corrosive liquids.

Can it work on a secure or offline site?

Yes. The Dropometer measures contact angle and surface tension with no network connection, after a one time licence activation. Drop images are captured and analysed on the phone, which your IT team can manage. It carries no security approval, so your security office decides whether a phone may enter. See offline and secure site measurement.

Can I screen insulating oil interfacial tension on site?

Yes, as a trend between lab tests. A water drop in the oil, read at a locked drop age, gives the interfacial tension by pendant drop. ASTM D2285 used drop weight, and ring methods remain the reference for reported results. Interfacial tension is one oil test among several, so read it alongside your other oil results.

How accurate is the Dropometer?

The drop shape method was validated against a KRUSS DSA100E in two peer reviewed papers, one in Review of Scientific Instruments and one in Colloids and Surfaces A. Published contact angle accuracy is 0.35 degrees. Researchers at the Harvard shared facility and a Concordia sensor thesis used it on device materials. See our validation papers.

Standards, evidence and resources

1. Industry standards Use cases Case studies Client citations (our analysis of each paper) Use case collections Further resources