Particle size polydispersity index

Particle Size, Polydispersity Index, and Zeta Potential Measurements... 

Particle size, polydispersity index, and zeta potential measurements of mannosylated liposomes are determined by Zetasizer nano ZS-90. 

This gives a good indication of the location of the distribution. The particle size polydispersity index, PSPI, on the other hand, gives an indication of the width of the distribution. The PSPI is defined as the mean squared radius divided by the mean radius squared,... 

The distribution of molecular weights of each generation was determined from measurements on about 50 molecules, with results shown in Figure 12.19 (the weight fraction is the percent dendrimer in each interval of molecular weight under consideration). Based on these distributions, the polydispersity index (.MJMa) of G5 to G10 can be calculated, with results shown in Table 12.1 [39], They are all less than 1.08, which means that the particle size distribution is very uniform for each generation. 

Figure 16 may also be used to illustrate the problem of polydispersity. For simplicity, consider a small polydispersity in particle size at constant refractive index. The theoretical surface shown in Figure 16 must be modified with a running integration over the size distribution which tends to fill in the minima and round off the maxima so that some of the structure is averaged out. Graphical illustrations of the effect have been reported (9) and the effect has been exploited to obtain both particle size and distribution width (10). It should be realized that both very narrow or very broad distributions tend... 

Since the PS reference sample is almost monodisperse, a cumulant analysis of that material would yield a very small Q, say Q < 0.03. That is, all the correction terms are negligible and Eqs. (17) collapse to Eqs. (12). But cumulant analysis is a useful way to handle practical samples such as pigments, inks, microemulsions, swollen micelles, globular proteins, and spherical virus particles, where there is a size distribution but one that is not very broad (say Q < 0.3). This analysis should be made for the milk data using a non-linem teast-squares fitting of Eq. (17a), neglecting /1.3 and all higher order terms. Report the F, D, and R values as well as the second cumulant /t2 aiid the polydispersity index Q. 

The microlatices prepared by polymerization are more advantageous, particle size and polydispersity index. 

As mentioned, in addition to the MMD and PSD, various average molar masses, particle sizes, and polydispersity indexes can be calculated from the FFF frac-tograms. If the detector response, h, is proportional to the mass of the macromolecules or particles, the mass-average molar mass or mass average particle diameter can be calculated from... 

When the ethanol ratio to water was 20% (v/v), the particle size of liposomes was less than 200 nm with a small value of polydisperse index (PI) (<0.1). However, at ethanol ratios of over 50% (v/v) the particle size of liposomes was more than 1000 nm (15). 

For technological reasons it is sometimes desirable to use a definite particle size fraction of a given compound. A priori, it is expected that the molecular mass and polydispersity do not depend on the particle size. Actually, gel permeation chromatography on a fractionated 10 mPa s EC sample showed some effect [22] the average molecular mass and the polydispersity index of the various size fractions ranged from ca. 18 800 to 24 800 and from 3,1 to 3.4, respectively. 

Styrene in water without surfactant. Although the polydispersity indexes for the synthesis of the polyNaSS macroalkoxyamine were rather low (1.2 < PDI < 1.3), no data were provided concerning the polymerization. The same observation can be made for the kinetic and macromolecular characteristics of the emulsion polymerization. Stable dispersions were obtained, but the solid content did not exceed 5wt%. The particle size distributions were quite broad and within the 50-200nm range. 

Intrinsic Sample viscosity code (q) Molecular weight (Mv) Sample code Particle size (nm) Polydispersity index (pdi)... 

Maa and Hsu (75) reported the formation of nano-particles by the double-emulsion method (W/OAV), using methylene chloride as an organic solvent and poly(vinyl alcohol) (PVA) or human serum albumin (HSA) as a surfactant. Experimental parameters such as the preparation temperature, the solvent-evaporation method, the internal aqueous phase volume, the surfactant concentration, and the polymer molecular weight were investigated for particle size, the zeta potential, the residual surfactant percentage, and the poly-dispersity index. Preparation parameters leading to particles with well-defined characteristics such as an average size around 200 nm and a polydispersity index lower than 0.1 were identified. 

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