Explicit role of ionic strength in retention behavior of polystyrene latex particles in sedimentation field-flow fractionation: Slip boundary model.

We investigate an explicit role of the ionic strength in the retention behaviors of polystyrene (PS) latex particles in sedimentation field-flow fractionation (SdFFF) by hinging upon the retention theory recently developed [1] asR=(R+v)/(1+v). Here R is an experimental retention ratio, and R is the analytical expression of the standard retention theory based on the parabolic flow velocity. The reduced boundary velocityv is expressed in terms of the ionic strength I of the carrier liquid as v=v/(1+εI), where v=0.

Separation and characterization of particles in natural water and soil using flow field-flow fractionation.

Flow field-flow fractionation (FlFFF) is used to characterize particles in natural water (ground and surface water) and soil. The opposed flow sample concentration (OFSC) mode of FlFFF (OFSC-FlFFF) is employed, where the colloidal sample is continuously fed into the channel so that the particles are focused into a narrow band near the inlet of the FlFFF channel before the separation is initiated. There is no need for stopping the flow for the sample relaxation, which is usually required in conventional FlFFF operations.

Repeatability and reproducibility of thermal field-flow fractionation in molecular weight determination of processed natural rubber.

The purpose of this study is (1) to determine the repeatability and reproducibility of thermal field-flow fractionation (ThFFF) in measuring the molecular weight of compounded natural rubber, and (2) to examine the correlation between the molecular weights obtained from ThFFF and the rheological data. 8 batches of compounded natural rubber were obtained from a thermo-mechanical mastication process, and were analyzed by ThFFF in a designed testing sequence. ThFFF analysis showed the compounded natural rubbers range in weight-average molecular weight (M(w)) from 143,000 to 360,000.