Solution and Surface Charge Properties of Shell Cross-Linked Knedel Nanoparticles

Abstract

Solution-state characterizations of poly(4-vinylpyridine):polystyrene (PVP:PS) shell crosslinked knedel nanoparticles (SCK's) are described. A combination of techniques, including dynamic light scattering, electrophoretic light scattering, and analytical ultracentrifugation, are used to determine the hydrodynamic diameter, surface charge characteristics, molecular weight, and aggregation number of the SCK's and their micelle precursors. The use of analytical ultracentrifugation is highlighted because of the wealth of information it provides in characterizing SCK solution behavior. The analysis of SCK's indicates that particle diameter, molecular weight, and aggregation increase with increasing PS chain length of the PVP:PS block copolymer used to prepare the SCK. Measurements of electrophoretic mobility and zeta potential via electrophoretic light scattering point to partial burial of charge below the particle surface of quaternized PVP units comprising the shell of the SCK. By contrast, the characterization of corresponding solution properties for the non-cross-linked micelle precursors is problematic due to significant particle heterogeneity and nonideal solution behavior. The comparison of solution data for SCK's and micelle precursors clearly indicates stabilization of SCK particles is achieved through shell cross-linking.

Chemically induced supramolecular reorganization of triblock copolymer assemblies: Trapping of intermediate states via a shell-crosslinking methodology

“…Subsequent intramicellar crosslinking by reaction with the diamine, 2,2Ј-(ethylenedioxy)bis(ethylamine), is conducted at periodic times as a strategy to preserve the intermediate morphologies for characterization. The establishment of covalent bonds between the polymer chains comprising supramolecular assemblies has been shown to generate robust nanomaterials (38)(39)(40) that are not subject to further reorganization events during the evaluation experiments. Therefore, this approach allows for the study of the phase-transition processes under a number of experimental conditions: in solution and in the solid state.…”

Preparation and Morphologies of Shell Cross-Linked Micelles Based on Commercial Poly(styrene-block-ethylene-co-butene-block-styrene)

“…[1][2][3][4][5][6][7][8][9][10] For those SCK's the size was smaller than the corresponding parent micelles because of the decreasing solubility of the shell component with shell cross-linking reaction. 15 However, in the present case the amination produces positively charged units in the shell, which increase swelling of the shell in THF/ethanol. In Figure 3b, the size distribution of the SCK micelles becomes narrow as indicated by the polydispersity index being 0.08 by DLS.…”

Synthesis of Gadolinium-Labeled Shell-Crosslinked Nanoparticles for Magnetic Resonance Imaging Applications

“…AFM imaging indicated the capability of the SCKs to flatten upon adsorption onto a solid substrate (mica), a result of favorable interactions and the nonrigid, fluid PMA core of the SCK nanoparticles. [14a,19,22] Analytical ultracentrifugation [23] (Fig. 1) demonstrated a unimodal distribution and, in conjunction with DLS and density determinations, gave a peak-average molecular weight of 2500 kDa (2500 kg mol ±1 ), corresponding to an aggregation number of 160 amphiphilic block copolymer chains per SCK.…”

“…A centrifugation time of 3±5 days was used to reach sedimentation equilibrium. The partial specific volumes (W) of the SCKs was determined via sedimentation equilibrium analysis for protonated and deuterated buffer solutions of SCKs, as previously described [23]. Solutions of the SCKs in deuterated www.afm-journal.de Adv.…”