![]() ![]() ![]() One can thus determine the particle size from an exponential fit to the autocorrelation and its decay time. Because large particles have higher friction and move more slowly in a liquid, the autocorrelation of the photon time trace decays more slowly than for small particles. The Time Tagger software calculates a fully logarithmic autocorrelation on the detected photon time trace. ![]() Detecting the speckle pattern with a single photon detector at a fixed angle and tracking the intensity of the scattered photons with the Time Tagger, one can observe a fluctuating intensity time trace corresponding to the Brownian motion of the nanoparticles. Shining coherent laser light onto the sample results in scattering by the particles, and a speckle pattern is visible. DLS measures these fluctuating motions and their characteristic time scale, which can then be related to the nanoparticle size distribution. Nanoparticles inside a solution undergo random movements, the so-called Brownian motion. DLS can measure nanoparticles as small as one nanometer and as big as a few microns. And therefore, if the tested sample is suitable or if unwanted agglomeration of the particles has occurred. One can see within seconds if the measured size of the dissolved nanoparticles is within expectations. DLS allows for fast and non-invasive verification of sample quality and ensures a stable production process. It is a well-established method in many areas that focus on nanoparticles, such as colloid and polymer science, pharma and food industries, and cosmetic and paint product development. Dynamic light scattering (DLS) is an optical analysis method for particle sizes in solutions. ![]()
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