Giant hollow fiber formation through self-assembly of oppositely charged polyelectrolyte brushes and gold nanoparticles

We report on the use of binary mixtures of oppositely charged gold nanoparticles (AuNPs) and spherical polyelectrolyte brushes (SPBs), consisting of a polystyrene core onto which long polystyrene sulfonate chains are grafted, as a simple model system to investigate the influence of directional interactions on self-assembly. We demonstrate that the mixing ratio, i.e., the number of AuNPs per SPB, has a profound influence on self-assembly. In particular we report on the formation of giant hollow fibers, and present a thorough characterization of these nanostructures. We speculate that the adsorption of a few AuNPs on the SPBs appears to direct the tubular self-assembly, and discuss the analogy to the case of modified proteins such as tubulin under the action of nucleotides

Charge-induced conformational changes of dendrimers

We study the effect of chargeable monomers on the conformation of dendrimers of low generation by computer simulations, employing bare Coulomb interactions. The presence of the latter leads to an increase in size of the dendrimer due to a combined effect of electrostatic repulsion and the presence of counterions within the dendrimer, and also enhances a shell-like structure for the monomers of different generations. In the resulting structures the bond-length between monomers, especially near the center, will increase to facilitate a more effective usage of space in the outer-regions of the dendrimer.Comment: 7 pages, 12 figure

Spherical Polymer Brushes

This chapter is devoted to spherical polymer brush particles bearing a densely packed layer of polymer chains on their surface, which exhibit well defined core shell morphologies. The survey on recent experimental and theoretical developments has demonstrated that spherical polymer brushes present a number of fundamental questions of high interest. In this review we have discussed, by drawing on selected examples of recent research, how spherical polymer brushes are paving the way from synthesis of designed system, characterization to advanced applications. Special attention has been paid to future perspectives of polymer brushes grafted to spherical supports that go beyond simple stabilization of particles through a surrounding brush layer. Possible applications, such as for the preparation of catalytically active metal nanoparticles and the immobilization of proteins, have been discussed in full detail. All results herein demonstrate that such particles may serve as carriers for catalytically active nanostructures, namely for metal nanoparticles and enzymes. In addition, applications in other fields including smart stabilizers for emulsions and as novel retention aids in papermaking industry have been discussed as well. Here interesting developments in nanotechnology are to be expected which make use of the strong responsiveness of the surface layer under external trigger