Various techniques are employed to characterize nanoparticles, each with its strengths and limitations:
Dynamic Light Scattering (DLS) DLS is commonly used to measure the size distribution of nanoparticles in suspension. It analyzes the fluctuations in light scattering due to the Brownian motion of particles. However, it may not be suitable for non-spherical particles.
Transmission Electron Microscopy (TEM) TEM provides high-resolution images of nanoparticles, allowing for detailed examination of their size, shape, and morphology. It requires complex sample preparation and is time-consuming.
Scanning Electron Microscopy (SEM) SEM offers surface images of nanoparticles, useful for studying their morphology and surface structure. It has lower resolution compared to TEM but requires simpler sample preparation.
X-ray Diffraction (XRD) XRD is used to determine the crystallinity and phase of nanoparticles. It can identify the crystal structure and composition but is less effective for amorphous materials.
Fourier Transform Infrared Spectroscopy (FTIR) FTIR analyzes the chemical composition and functional groups on the surface of nanoparticles. It is essential for understanding surface modifications and interactions.
Brunauer-Emmett-Teller (BET) Analysis BET measures the surface area and porosity of nanoparticles by nitrogen adsorption-desorption isotherms. It is crucial for applications requiring high surface areas, such as catalysis.
