Effect of preparation conditions on the size of nanoparticles based on poly(D,L-lactide-co-glycolide) synthesized with bismuth subsalicylate

Fabrication and mechanism study of the nitrocellulose aqueous dispersions by solvent displacement method

“…In addition, numerous studies have pointed out that for NPs prepared following the nucleationagglomeration mechanism, the particles size should be linearly dependent on the concentration of the organic phase in double logarithmic coordinates, and the slope is about 1/3 when the size of the obtained particles is only affected by the initial concentration. 19,21,26,34 As seen in Figure 2b, the NC particle size prepared herein is linearly dependent on the NC acetone solution concentration in double logarithmic coordinates, which further supported the assumption that the formation of NC NPs followed the nucleation and aggregation mechanism. However, the fitted slope is about 0.56, which is much larger than 1/3, indicating that the size of nitrocellulose NPs was not only dependent on the initial concentration of the NC solutions.…”

“…Therefore, according to the nucleation‐agglomeration mechanism, if the preparation time is kept constant at different concentration conditions, the size of the particles should be proportional to the mass fraction of the polymer, 25 which is consistent with the phenomenon observed in the preparation process of NC aqueous dispersions. In addition, numerous studies have pointed out that for NPs prepared following the nucleation‐agglomeration mechanism, the particles size should be linearly dependent on the concentration of the organic phase in double logarithmic coordinates, and the slope is about 1/3 when the size of the obtained particles is only affected by the initial concentration 19,21,26,34 …”

“…Among the different methods described for nanoemulsion preparation, the solvent displacement method (or spontaneous emulsification, or nanoprecipitation) is a straightforward and fast process 15–19 . In this method, the hydrophobic solute is first dissolved in a water‐miscible organic solvent (usually ethanol, acetone, or tetrahydrofuran) to form the organic phase and this solution is then added to a certain amount of non‐solvent under continuous gentle magnetic stirring followed by the evaporation of the organic solvent 20,21 . Differing from emulsion‐based methods, the solvent replacement method does not require the involvement of emulsifiers, 20,22 and the polymer particles can form spontaneously without external energy input 23 .…”

“…[15][16][17][18][19] In this method, the hydrophobic solute is first dissolved in a water-miscible organic solvent (usually ethanol, acetone, or tetrahydrofuran) to form the organic phase and this solution is then added to a certain amount of non-solvent under continuous gentle magnetic stirring followed by the evaporation of the organic solvent. 20,21 Differing from emulsion-based methods, the solvent replacement method does not require the involvement of emulsifiers, 20,22 and the polymer particles can form spontaneously without external energy input. 23 Xia et al 24 prepared ethylcellulose aqueous dispersion by solvent replacement method without using any emulsifier.…”

The Role of Integrated Approach in the Determination of Nanoparticle Sizes in Dispersions

“…Secondly, polymeric NPs of the "core-corona" and "Janus" types can be studied by TEM only with the use of the selective contrasting procedure [15]. For example, to employ TEM for studying polymeric "core-corona" NPs, which are formed from amphiphilic block copolymers, such as poly(lactide)-block-poly(ethylene oxide) (PLA-b-PEO) [16,17], as well as hydrophobic PLGA copolymers in the presence of PVA as a hydrophilic stabilizer [18,19], toxic uranyl acetate is commonly used as a negative contrasting agent. In addition, when samples are dried at the stage of sample preparation, the stabilizing corona of particles collapses, and the D value determined for NPs by the TEM method turns out to be significantly lower than the value of their D h .…”