The absorption and scattering of UV radiation are typically measured using various spectroscopic techniques. Here are some common methods:
UV-Visible Spectroscopy
UV-Visible spectroscopy is a widely used technique for measuring the absorption of UV radiation by materials. In this method, a beam of UV light is passed through a sample, and the amount of light absorbed at different wavelengths is measured using a spectrophotometer. By analysing the absorption spectrum, information about the absorbance of UV radiation by the material can be obtained.
Diffuse Reflectance Spectroscopy
Diffuse reflectance spectroscopy is often used to measure the scattering of UV radiation by materials. In this technique, a sample is illuminated with UV light, and the intensity of the light reflected at different angles is measured. By analyzing the angular dependence of the reflected light, information about the scattering properties of the material can be determined.
Transmittance Measurements
Transmittance measurements involve passing a beam of UV light through a sample and measuring the intensity of the transmitted light. By comparing the intensity of the incident light with the intensity of the transmitted light, the transmittance of the material can be determined. From transmittance measurements, information about the absorption and scattering of UV radiation by the material can be inferred.
Electron Microscopy
Electron microscopy techniques, such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM), can be used to directly visualize the morphology and structure of materials at the nanoscale. These techniques can provide insights into the size, shape, and distribution of nanoparticles or other structures that contribute to the absorption and scattering of UV radiation.
Dynamic Light Scattering (DLS)
Dynamic light scattering is a technique used to measure the size distribution of particles in a sample by analysing the fluctuations in the intensity of scattered light. By performing DLS measurements, information about the size and distribution of nanoparticles or other scattering centres in a material can be obtained, which can help understand their contribution to UV scattering.
These methods are commonly used in research and industrial settings to characterize the absorption and scattering properties of materials, including those used for UV protection in plastics, polymers, and other applications.