Spherical polyelectrolyte brushes chains

Figure 6.17 Schematic representation of a spherical polyelectrolyte brush in which linear chains of poly(acrylic acid) (PAA) are chemically grafted onto the surface of a colloidal polystyrene (PS) particle. L denotes thickness of the PAA brush. (After Guo and Ballauff, 2000.)...

Figure 1.1. (a) Stmeture of the spherical polyelectrolyte brushes having cationic polyelectrolyte chains on their surface. The core consists of poly(styrene) and has diameters of approximately 100 nm. The chains are densely grafted to the surface of these cores by a grafting-from technique ( photoemulsion polymerization, cf. Ref. 24). (b) The core-shell microgel particles shown in a schematic fashion The core consists of poly(styrene) (PS) whereas the network consists of poly(iV-isopropylacrylamide) (PNIPA) crosslinked by JVdV -methylenebisacrylamide (BIS). 

The capability of combined nanoscale spatial and millisecond time resolution provided by SAXS is clearly revealed by a study involving the absorption of bovine serum albumin (BSA) onto spherical polyelectrolyte brushes (SPB). The experiment also highlighted the requirement of an advanced modeling capability for the complete exploration of the time-resolved SAXS data. The quantity of absorbed protein per brush as a function of time was provided from the radial electron density profile of SPB, which has been previously derived from the time-resolved SAXS intensities. Furthermore, an unexpected subdiffusive motion of proteins in the tethered polyelectrolyte brushes has been revealed. A quantitative explanation of this sub-diffusive mode can be approached in terms of a simple model involving direct motions of proteins enclosed in the effective interaction potential of the polyelectrolyte chains. 

An example of the conformation of long polyelectrolyte chains attached to colloidal latex particles is also shown here by cryo-TEM [590]. The dense grafting of the polyelectrolyte chains ( spherical polyelectrolyte brush, or SPB) leads to a confinement of the counterions... 

The distinctive features of spherical polyelectrolyte brushes (SPB) as ideal nanoreactors are discussed. SPB containing colloidal particles on which polyelectrolyte chains have been densely grafted offer a wide range of potential applications. They are ideally suited for the generation and immobilization of metal or metal oxide nanoparticles, which can be applied as smart catalysts in chemical industry. SPB can also be used for immobilization of proteins and enzymes. The response to external stimuli makes SPB unique in the field of nanoreactors. 

Spherical polyelectrolyte brushes (SPB) consist of a spherical core of polymeric material, where linear PE chains are attached either by covalent bond or by physical adsorption (BaUauff, 2007 Blencowe et al., 2009 Xu et al., 2010a). A schematic diagram is shown in Fig. 4.1. 

In this chapter, we review recent work on two special types of polymerie earrier systems, namely, the spherical polyelectrolyte bmshes (SPBs) and thermosensitive core-shell microgels, which have been used successfully for the immobilization of metal nanopartieles. Figure 1.1a gives a schematic representation of the SPB particles Long linear polyelectrolyte chains are grafted densely to a colloidal core particle. The term brush implies that the grafting of the chains is sufficiently... 

Abstract This chapter summarizes the influence of polyelectrolyte topology oti biological functions and biomedical applications such as cell uptake, drug delivery, and gene transfection. Polyelectrolytes utilized are spherical structures derived from dendrimers and albumin or cylindrical brushes, all of which are decorated with various polypeptide chains. 

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