1Water droplet angle testeroperating procedure
Environment Preparation
Instrument placement: Choose a dry and windless experimental environment to avoid wind or vibration interference with water droplet morphology. The instrument should be placed horizontally on a stable table to ensure stability.
Temperature and humidity control: Maintain stable room temperature (such as 25 ℃± 1 ℃), stable humidity (such as<60%), and reduce the influence of environmental factors on water surface tension.
Instrument inspection and start-up
Hardware inspection: Confirm that the power and data cables are securely connected, and that all components of the instrument (such as the drip system, microscope, and light source) are not damaged.
Software connection: Connect the instrument to the computer, install and open the accompanying software, and ensure that the software version is compatible with the instrument.
Preheating and Calibration:
Preheat the instrument for 10-15 minutes to ensure the stability of the optical system.
Use standard samples (such as distilled water) for calibration, adjust the light source, camera position, and parameters (such as brightness and contrast) to ensure clear images.
Sample preparation
Cleaning treatment: Clean the surface of the sample with deionized water or appropriate solvents to remove oil stains, fingerprints, and other pollutants, and dry naturally or blow dry with nitrogen gas.
Flatness inspection: Ensure that the surface of the sample is flat, without scratches or unevenness, to avoid affecting the droplet shape.
Fixed sample: Place the sample on the test plate and secure it with a clamp to ensure it is parallel and stable with the test plate.
Droplet generation and release
Droplet volume control: Use a microsyringe or automatic drip system to add 1-5 μ L of droplets (usually 2 μ L), ensuring consistent droplet size.
Release method: Manually or automatically release the droplets to ensure they fall smoothly onto the surface of the sample, avoiding impact or splashing.
Image capture and angle measurement
Image capture: After the droplet stabilizes (usually 0.1-1 second), use a camera to capture high-resolution images (such as 3 million pixels) to ensure clear edges of the droplet.
Angle measurement:
Use software automatic analysis functions (such as Young Laplace equation fitting, ellipse fitting method) to calculate the contact angle.
Manually adjust the measuring ruler to be tangent to the edge of the droplet and record the contact angle value.
Multiple measurements: Repeat measurements 3-5 times at different locations and take the average to improve accuracy.
Data recording and report generation
Record content: including contact angle values, testing conditions (temperature and humidity, droplet volume), sample information, etc.
Report generation: Export data to Word, Excel, or PDF format, with test images and calibration data attached.
Instrument cleaning and shutdown
Cleaning the instrument: Wipe the surface of the instrument and the test plate with a clean cotton cloth to avoid residue affecting the next test.
Turn off the instrument: Turn off the software and power switch, unplug the power cord, and store the instrument in a dry and ventilated place.
IIWater droplet angle testerPrecautions
Operating Specifications
Wear dust-free gloves throughout the process: to avoid finger oil contamination of the sample or lens.
Droplet location: Priority should be given to selecting the center or edge area of the sample to avoid interference from boundary effects.
Avoid vibration: Keep the instrument stationary during the testing process to prevent changes in droplet morphology.
Sample processing
Cleanliness requirement: Surface contamination of the sample can cause an abnormal increase in contact angle (such as increased hydrophobicity due to oil stains).
Special sample processing:
Coating sample: It is necessary to confirm the uniformity of the coating to avoid local thickness differences affecting the results.
Flexible samples: Avoid excessive stretching and surface deformation when using fixtures for fixation.
Droplet control
Consistency of droplet volume: Droplets that are too large (>5 μ L) may have irregular shapes due to gravity, while droplets that are too small (<1 μ L) may have difficulty capturing clear images.
Droplet temperature: Ensure that the droplet is at the same temperature as the sample to avoid thermal expansion and contraction affecting the contact angle.
instrument maintenance
Regular calibration: Calibrate at least once a week or adjust according to usage frequency.
Component inspection: Check the working status of components such as the light source, camera, and drip system every month, and replace aging components in a timely manner.
Storage environment: When not in use for a long time, cover the instrument with a dust cover to avoid direct sunlight or humid environments.
safe operation
Power safety: Use a standard power adapter to avoid voltage fluctuations that can damage the instrument.
Chemical reagent treatment: If using organic solvents to clean samples, it is necessary to operate in a fume hood to prevent volatilization hazards.