End-functionalized polymers in colloidal

Light Scattering Studies of Adsorption of End-Functionalized Polymers in Colloidal... 

In the above discussion we have assumed that the polymer molecules are free in the solution, so that they scatter light individually. When the end-functionalized polymer is added into the colloidal suspension, some of the polymer molecules adsorb on the surface of the colloidal particle, and form colloid-polymer micelles. If all the polymer molecules adsorb on the colloidal surfaces (complete adsorption), the mixture can be viewed as a single-component system consisting of only colloid-polymer micelles. In this case the standard virial expansion for the scattering light intensity is still valid, and Eq. (1) becomes ... 

The upper solid curve in Fig. 3a is a plot of Eq. (4) with /2//1 =0.11. The equation for the non-adsorption mixture fits the data well. Our previous study of the same system also suggests that the PEP polymer does not adsorb onto the colloidal spheres. The two end-functionalized polymers are found to be partially adsorbed onto the colloidal surfaces. The lower solid curve in Fig. 3a is a fit to Eq. (8) with ao = 0.21. In the range 0 < a < 24, ao is found to be independent of the molar ratio u. In this range of a , the overall polymer concentration P2 is below the polymer overlap concentration. The zwitterion-PEP data can also be fitted to Eq. (8) with a constant ao = 0.18. The dashed curve in Fig. 3b is a plot of Eq. (8) with a = 1 (complete adsorption). One can immediately see from Fig. 3 that the measured y(u ,ao) for our end-functionalized polymers lies in-between the non-adsorption and complete adsorption curves. 

In this paper, we use both numerical and analytical self-consistent field (SCF) models to isolate a robust scheme for creating stable dispersions from polymers and clays that are immiscible. Specifically, we show that adding a small fraction of end-functionalized polymers to a melt can lead to the formation of exfoliated structures, where the clay sheets are uniformly dispersed within the polymer matrix. Our findings reveal that the ideal pol eric candidates for creating stable exfoliated composites are those that would constitute optimal steric stabilizers for colloidal suspensions. This prediction provides new design criteria for fabricating polymer/clay composites with the... 

In describing the mechanical response of microstructured fluids, e.g., polymers, emulsions, colloidal dispersions, etc., one needs to determine the pair distribution function - the probability density P(r) for finding a particle at a position r given a particle at the origin in suspensions, or the probability density of the end-to-end vector in polymers, or a measure of the deformation of drops in an emulsion. This probability density satisfies an advection-diffusion or Smoluchowski equation of the following (when suitable approximations have been made) form ... 

In the above, e is the adsorption energy between the end-functional group and the colloidal surface, and AS is the entropy loss for a free polymer chain to anchor to the colloidal surface. 

Thermoresponsive polymer brushes on 20 nm colloidal gold formed through ATRP of W-isopropyl acrylamide in aqueous media End-functionalized 3D self-assembled monolayers (SAMs) on GNPs by living cationic ring-opening polymerization reaction directly on GNP surfaces... 

To a large extent the end-use requirements can be satisfied by the bulk polymer properties the other requirements are dictated by surface and colloidal properties. The bulk properties are usually determined by a handful of monomers as shown in Table 6.1. Crosslinking, surface and colloidal properties are governed by functional monomers which are described in Section 6.2.3. 

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