Contact Angle/Surface Tension Measurement Analytical Service

Overview

The Contact Angle/Surface Tension Measurement Instrument is primarily used for measuring the contact angle of liquids on materials, assessing surface treatment processes, testing surface cleanliness, and studying the adhesion and stability of coating processes. This instrument has broad applications across various fields, including materials science, biology, and environmental science:

1. In Materials Science: It is widely used to study properties such as wettability, adhesion, and stickiness of materials. For instance, by measuring the contact angle of different liquids on various material surfaces, insights can be gained into the wettability of these liquids on the materials, helping to predict their performance in practical applications.

2. In Biological Sciences: The instrument is also commonly used to measure cell adhesion on different material surfaces. By observing the contact angle of cells on surfaces, researchers can gain insights into cell adhesion properties, which is important for studying cell morphology changes, functional expression, and more.

3. In Environmental Science: The instrument plays a vital role by measuring the contact angle of water droplets on natural surfaces like soil and rock. This helps determine the water absorption capacity of these surfaces, which is useful for assessing soil water retention and rock stability.

Measurement Principles 

1. Image Analysis Method: This method is based on a specific mathematical model, where a droplet is viewed as part of a sphere or cone. The contact angle is calculated by measuring specific parameters, such as width/height, or by direct fitting. The Young-Laplace equation describes the relationship between the pressure difference across a closed interface and the curvature and interfacial tension, allowing for an accurate description of the profile of an axisymmetric droplet, from which the contact angle can be determined.

2. Wilhelmy Plate Method: When a solid plate is inserted into a liquid, the liquid surface remains straight and reaches the three-phase contact line only when the angle between the plate and liquid surface is exactly the contact angle; otherwise, the surface will curve. By adjusting the insertion angle of the plate until no curvature appears near the three-phase contact line, the angle between the plate and the liquid surface at this point becomes the contact angle.

3. Three-Force Measurement Method: When a solid sample plate is immersed in the test liquid, surface tension and the surface free energy of the solid cause a downward force measured by a weight sensor. The specific calculation formula is F = γlgcosθP, where P is the perimeter of the plate. By knowing the measured force, the contact angle θ can be determined.

4. Permeability Measurement Method: In a tube filled with powder, the gaps between solid particles act like capillaries. Due to capillary action, a liquid that wets the surface of the solid powder penetrates the powder column. Since capillary action depends on the surface tension of the liquid and the contact angle with the solid, measuring the permeability of a liquid with known surface tension in the powder column provides the contact angle of the liquid with the powder

Testing Procedure

Different sample types require specific testing steps. The general testing steps are as follows (for reference only):

1. Bulk/Film Sample Testing Steps:
   Select a sample of suitable size and place it on the contact angle testing platform. Using the equipment’s automatic titration system, apply the appropriate reagent (e.g., a water droplet) onto the sample. Capture a test image and measure the contact angle using the volume method, fitting method, or angle measurement method (the specific method depends on actual conditions).

2. Liquid Sample Testing Steps:
   Prepare the required liquid sample, ensuring its purity and stability. Clean the solid specimen to ensure the surface is clean and free of contamination. Drop the liquid sample onto the specimen surface, ensuring the drop volume is appropriate to avoid overflow. Open the contact angle measurement software and configure relevant settings, such as selecting the appropriate measurement mode and parameters. Slowly move the instrument’s probe to the point of contact between the droplet and the specimen surface. Wait for a period to allow the droplet and specimen surface to reach equilibrium before conducting the test.

3. Powder Sample Testing Steps:
   Powder samples need to be compressed into pellets. First, clean and dry the compression mold, then evenly spread the powder sample in the mold. Assemble the mold and place it on a press to apply pressure. Finally, release the pressure, open the mold, and remove the sample, placing it on a slide for testing.

Results Example

Static Contact Angle: Image with labeled contact angle:

Advancing angle / receding angle / rolling angle test values provided:

Surface/interfacial tension: Provide test values or software screenshots:

Bounce Test: Default includes a video of the bounce process and three images:

Instrument Models: Dataphysics OCA20, Dataphysics, DCAT21, DSA100, etc.

Sample Requirement

• Bulk/Film Sample Requirements: For each test, samples should be larger than 1 cm x 1 cm and as flat as possible. If parallel testing is needed, please provide the corresponding number of samples.

• Powder Sample Requirements: Typically, powder samples need to be pressed into pellets before testing. For contact angle measurements, direct testing is possible, but for pellet testing, prepare samples according to the required number of parallel tests (typically, two tests require 0.5 ml; three tests require 1 ml). For direct powder testing, a minimum of 200 mg is required. Surface/interfacial tension tests require 50 ml of each liquid sample. If the amount is insufficient, please consult with the project manager. Solid samples must be capable of being heated and melted if needed.

• Fiber Requirements: The test length should be no less than 30 cm.

• Bounce Test: Generally intended for superhydrophobic samples where water droplets quickly bounce off the surface, indicating superhydrophobic properties. A static contact angle of 145° or more is generally required to achieve the bouncing effect. If the static contact angle does not meet or approach the superhydrophobic range, sample submission is not recommended.

• Other Requirements: The standard medium for contact angle testing is water. If other reagents are needed, please provide them yourself, with at least 2 ml.

* The price on our website is for reference only. 

* Note: Data analysis service is not included in the list prices.

Highlights: High Quality Data, Competitive Pricing, Technical Support by Scientists.

Analytical Service Minimum order requirement: $250 per order. A $200 handling fee will be applied if order is below $250.

Please contact sales@msesupplies.com for additional information and instructions on our Analytical Services program. Confirmation of the sample(s) requirements, SDS sheets and additional information is needed prior to processing the Analytical Service order. 

***Please do not ship any samples without authorization from MSE Supplies***