Equally at the isoelectric point, the size of clusters based on the homoPEs (PDADMAC and PEI) increased however rapidly below the critical ionic strength . At the end of dilution, the
size of the large aggregates is superior to 1 μm and the aggregates sediment at the bottom of tube, which suggests that the interactions are stronger with homoPEs HDAC inhibitor than with the diblock. For the dispersions AP26113 nmr prepared from homoPEs at Z = 0.3 and Z = 7, we found the clusters of smaller sizes (D H ~ 500 nm) and we did not find a sedimentation until the end of dilution process. These results confirmed the existence of ‘arrested state’ at the two sides of ioelectric point. In this work, the desalting transition was shown to be a general process for homoPEs. The effective screening was found for PDADMAC and PEI but not for PAH. For this later system, even at 3 M, the oppositely charged species interacted
strongly and large aggregates were formed (D H = 400 nm, shown in Figure 6). Figure 6 Ionic strength dependence of the hydrodynamic diameter BMN 673 order D H . For a dispersion containing γ-Fe2O3-PAA2K particles and oppositely charged PAH polymers. With decreasing I S , no abrupt transition was observed. Dialysis Since the effective screening effects were evidenced for PDADMAC and PEI, we then investigate the dialysis process of PDADMAC/NPs and PEI/NPs salted dispersion at Z = 0.3, Z = 1, and Z = 7. In fact, dialysis and
dilution experiments are both based on the same desalting procedure. During the dialysis, the NPs and polymers are kept inside the membrane (10 KD MWCO) of the dialysis cassette. After 1 h of dialysis, we obtained spherical clusters formed by PDADMAC and by PEI, respectively. 4-Aminobutyrate aminotransferase Their hydrodynamic diameters D H , determined by using Zetasizer Nano ZS Malvern Instrument, were in good agreement with the results obtained in dilution experiments (see Table 4). Moreover, we anticipate that the clusters made with an excess of polymers should be positively charged and those with an excess of nanoparticles negatively charged, while the clusters obtained at isoelectric point should be neutral. In this work, electrokinetic measurements were performed on these cluster dispersions to determine their electrophoretic mobility μ E and ζ-potential (shown in Table 4). The intensities distributions of μ E are shown in Figure 7. At Z = 0.3 and 7, μ E is centered around +3 × 10−4 cm2 V−1 s−1 and −2.1 × 10−4 cm2 V−1 s−1, respectively for both PDADMAC and PEI. At Z = 1, μ E is approximately 0 for both copolymer and homoPEs. For PDADMAC and PEI, their intensity distribution of μ E (Figure 7b,c) clearly showed a charge inversion of the resulted clusters, passing from negative values (at Z = 7) to neutral charges (at Z = 1), then pass to negative value (at Z = 0.3).