On the Determination of Ostwald Ripening Rates from Dynamic Light Scattering Measurements

Abstract

The Ostwald ripening rate of several alkane in water emulsions stabilized by a nonionic surfactant is determined from dynamic light scattering (DLS) measurements. With the aid of computer simulations, the intensity weighted droplet radii obtained with DLS are converted to number averages, by taking the form of the droplet size distributionwhich evolves continuously toward a stationary distributioninto account. Thereby the effect of the transition from an initial, log-normal size distribution toward its stationary form is included. Second a model is proposed to account for the effect of the finite size of the surfactant layer (surrounding each oil droplet) on the measured particle size and thus on the ripening rate. It is found that both the effect of the transition from a nonstationary regime toward the stationary Lifshitz−Slyozov−Wagner regime and the effect of the finite size of the surfactant layer influence the ripening rates significantly.

Synthesis of near‐infrared‐emitting CdTeSe and CdZnTeSe quantum dots

“…The evolution of PL peak wavelength in respect to percentage composition of tellurium is summarized in Table 1 and Fig. The linear function of Vegard's Law: E alloy = xE A + (1x) E B , where x is the mole fraction, E A , E B , and E alloy are the properties of pure A, pure B, and the alloy A x B 1-x , respectively, had been confirmed by many alloyed materials (20)(21)(22)(23). As the content of tellurium increases, the PL peak wavelength first increases then decreases.…”

Semiconductor Quantum Dots as Multicolor and Ultrasensitive Biological Labels

“…In this process, smaller nanocrystals are broken down, and the dissolved atoms are transferred to larger nanocrystals. The rate of growth is dependent upon temperature and the amount of limiting reagents [31,32]. Alternatively, continuous injection of organometal/chalcogenide precursors at 300 8C can be used to increase the size of quantum dots [33].…”

Voltammetric determination of the critical micellar concentration of surfactants by using a boron doped diamond anode

“…A number of methods, including for examples the measurements of surface tension [5][6][7], light scattering [8], speed of sound [9], have been used. A review of electrochemical methods was recently published by Nesmerak and Nemcova [10]; potentiometry, electrical conductivity, voltammetry, capillary electrophoresis, have been successfully used for the determination of the CMC of various surfactants.…”