Definition
The Dyne Pen is a portable surface tension testing tool that quickly evaluates the surface energy or surface tension of a material by the wetting behavior formed on the surface of a material by a specific concentration of the test solution. Its measurement results are usually measured in dynes per centimeter, so they are often called dyne pens. This tool is widely used in industrial production and laboratory environments to qualitatively or semi-quantitatively judge the surface treatment effect of materials and their adaptability to subsequent processes.
Principle
The working principle of the dyne pen is based on the phenomenon of wetting the liquid on a solid surface. When the test droplet touches the surface of the material, if the surface tension of the liquid is lower than the surface energy of the material, the droplet will spread out. If it is higher than the surface energy of the material, the droplets remain bead-shaped. The DINE pen contains a test solution with known surface tension, and its tension values are usually identified as a gradient. By observing the wetting state of the test solution on the surface of the material with different tension values, the critical value of the surface energy of the material can be roughly determined. The process follows the basic relationship described by Young's equation, that is, the solid-liquid-gas three-phase interfacial tension equilibrium:
γSV = γSL + γLV cosθ
Among them, γSVIt is a solid surface energy and γSLIt is the tension of the solid-liquid interface, γLVis the surface tension of the liquid, and θ is the contact angle. When θ approaches 0°, the corresponding test liquid tension value can be regarded as an approximate indication of the surface energy of the material.
Measurement method
When measuring, a flat, clean representative area should be selected on the surface of the material to be measured. Place the dyne tip perpendicular to the surface and apply moderate pressure to evenly coat the test solution to form a liquid film about 25 mm wide. Observe the liquid film state within two seconds: if the liquid film is continuous and complete, it indicates that the surface of the material can be higher than the test liquid tension; If the liquid film shrinks into droplets, the surface of the material can be lower than the test liquid tension. By testing test pens with adjacent tension values, the highest tension value that keeps the liquid film continuous can be determined, which is a dyne-level approximation of the surface energy of the material. Tests should be performed under standard environmental conditions and avoid cross-contamination.
Influencing factors
Measurement results are influenced by a variety of factors. Material surface cleanliness is a critical factor, and dust, grease, or release agent residues can significantly reduce apparent surface energy. Ambient temperature and humidity may affect the volatilization rate and surface tension of the test fluid. The storage conditions and expiration date of the test solution will affect the accuracy of its calibrated tension value. Consistency in manipulation, such as application pressure and speed, can also introduce observational bias. The inhomogeneity of the microscopic morphology and chemical composition of the material itself can lead to local measurement differences. Therefore, it is recommended to carry out regular verification with standard samples and indicate the test conditions in the report.
Application:
The Dyne pen has application value in several industrial fields. In the printing and coating industry, it is used to evaluate the surface treatment of plastic, metal or ceramic substrates and predict ink or coating adhesion. In the electronics manufacturing industry, it assists in testing the surface cleanliness and solderability of circuit boards or packaging materials. In plastic welding and bonding processes, it is used to monitor the degree of surface activation of materials. In the field of packaging materials, it helps to judge the printability and composite strength of films. In addition, in the quality control process, the dyne pen can be used for rapid screening of the production line and comprehensive evaluation with laboratory precision instruments.
Selection
Measurement range and resolution should be considered when selecting. Common dyne pens typically have a test fluid tension range of between 30 and 70 dynes per centimeter, with some models extending to lower or higher ranges. Depending on the material's intended surface, a pen set that covers the corresponding range is selected, with gradient intervals typically ranging from 2 to 5 dynes per centimeter. It is necessary to confirm the chemical compatibility of the test solution solvent with the material to be tested to avoid dissolution or corrosion. For special environments, low-volatile or quick-drying formulations are available. In addition, the completeness of the technical documentation provided by the supplier, including calibration basis, storage requirements, and safety data descriptions, should be considered. It is recommended to verify the suitability and repeatability of the pen set through actual sample testing.