The hydrophilic and hydrophobic properties of the fiber surface have a significant impact on the application of fibers, e.g. in textiles, filters, medical and other fields. Therefore, accurately testing the hydrophilicity and hydrophobicity of fiber surfaces is essential for the research and development of novel fiber materials. In this article, we will introduce several commonly used methods for testing the hydrophilicity and hydrophobicity of fiber surfaces, and explain their principles and applications in detail.
1.Contact angle measurement.
Contact angle measurement is a commonly used method to test the hydrophilicity and hydrophobicity of fiber surfaces. This method evaluates the hydrophilicity and hydrophobicity of the fiber surface by observing the size of the contact angle of the water droplets on the fiber surface. The smaller the contact angle, the more hydrophilic the fiber surface is. Conversely, the larger the contact angle, the more hydrophobic the fiber surface. The contact angle measurement method has the advantages of simplicity, intuitiveness, and good repeatability, and is suitable for hydrophilic and hydrophobic testing of various fiber surfaces.
2.Hygroscopicity test method.
The hygroscopicity test method evaluates the hydrophilicity and hydrophobicity of the fiber surface by measuring the moisture absorption performance of the fiber in different humidity environments. In general, the fiber has better moisture absorption performance in the environment with high relative humidity, indicating that the fiber surface is more hydrophilic; Conversely, in an environment with low relative humidity, the fiber has poor moisture absorption, indicating that the fiber surface is more hydrophobic. The hygroscopic test method is suitable for evaluating the dynamic hydrophilic and hydrophobic properties of fibers, but the test cycle is long and requires specific environmental conditions.
3.X-ray photoelectron spectroscopy.
X-ray photoelectron spectroscopy is a method that analyzes the chemical properties of fiber surfaces by measuring the photoelectron spectroscopy of elements on the surface of fibers. By analyzing the chemical bonding state of elements on the fiber surface, the hydrophilicity and hydrophobicity of the fiber surface can be assessed. In general, the more polar chemical bonding states, the more hydrophilic the fiber surface is; Conversely, the more non-polar chemical bonding states, the more hydrophobic the fiber surface. X-ray photoelectron spectroscopy has the advantages of high accuracy and can analyze the chemical bonding state of elements on the fiber surface, but the test cost is high.
4.Atomic force microscopy.
Atomic force microscopy is a method to assess the hydrophilicity and rephobicity of fiber surfaces by observing the morphology and roughness of fiber surfaces. In general, the higher the morphology and roughness of the fiber surface, the more hydrophilic the fiber surface is. Conversely, the lower the surface topography and roughness, the more hydrophobic the fiber surface. Atomic force microscopy has the advantages of high resolution and observation of the microstructure of the fiber surface, but it is also expensive to test.
Four commonly used methods to test the hydrophilicity and hydrophobicity of fiber surfaces: contact angle measurement, hygroscopicity test, X-ray photoelectron spectroscopy, and atomic force microscopy. Each of these methods has its own advantages and disadvantages, and the appropriate test method can be selected according to the specific needs. Understanding and mastering these test methods is of great significance for the research and development of new fiber materials. In the future, with the continuous progress of science and technology, it is believed that more efficient and accurate test methods will be applied to the study of hydrophilicity and hydrophobicity of fiber surfaces.