Capillary dynamic light scattering: Continuous hydrodynamic particle size from the nano to the micro-scale

Micron-Sized Silica-PNIPAM Core-Shell Microgels with Tunable Shell-To-Core Ratio

“…Here, we want to note that our larger CS microgels seemed to be under the effect of gravitational settling during the DLS measurements, which could be the reason for their higher polydispersities (or overestimation of polydispersity) compared to the smaller microgels. Although the commonly quoted upper size limit for DLS is around 10 μm, it often is only achievable by increasing the viscosity of the continuous phase or by using capillary DLS [ 25 , 26 ]. In this study, however, we do not further discuss the matter and report the D h values as recorded and used for the calculation of δ.…”

An optimized filling method for capillary DLS

“…The rate at which the particles diffuse is exquisitely sensitive to forms of particle motion other than diffusion, such as gravitational settling and bulk thermodynamic fluid flow in the thermally controlled cuvette. A careful analysis of the different relaxation times in the time-correlated data [1], failed to reproduce the timescales typically associated with gravitational settling, the uncertainty long assumed to be the limiting factor for the upper size limit of DLS measurements. Convective motion within the capillary cell was carefully modelled using ANSYS and the timescales associated with convective motion were identified in the correlogram.…”

“…Capillary DLS seeks to suppress the convective motion within the sample, whilst maintaining excellent thermal control of the sample by conduction, with good thermal contact between a metal capillary holder and capillary outer surface, over the length of the capillary. It was discovered that 1.00 mm × 1.00 mm was an optimum size for the square capillary internal cross section [1] as a balance between the need to suppress the convective motion and reduce the sample volume, with the need to be able to reproducibly mount and align the capillary with the optical path within the instrument. The capillaries used in this work are 50 mm in length making them easy to handle, however, the 1.0 mm × 1.0 mm aperture means that care is needed in loading the sample into the capillary bore.…”

Practical Guidelines for the Characterization and Quality Control of Nanoparticles in the Pharmaceutical Industry

“…Acoustic techniques 32,43 DLS 13,23,26,28,29,44,45 Single -Direct method EM 23,26,29,31 AFM 23,50 -Indirect method NTA 23,26,29 TRPS 23,29,51 sp-ICP-MS 47,52 ES-DMA 53,54 Separative AUC 55,56 CE [57][58][59] DCS (known as CLS)…”