Nanoscopic Polymer Particles with a Well‐Defined Surface: Synthesis, Characterization, and Properties

Abstract

We review our recent work on polymeric latex particles having a well‐defined surface of grafted polymers. Two types of particles are discussed: i) particles with a thermosensitive shell, and ii) particles bearing a dense layer of linear polyelectrolyte chains on their surface (“spherical polyelectrolyte brush”). Both types of particles consist of a polystyrene core onto which either linear or crosslinked chains are grafted. The synthesis of these core–shell particles proceeds in a two‐step process which is reviewed in detail. In particular, we discuss the photo‐emulsion polymerization used for the synthesis of the spherical polyelectrolyte brushes. Most of the studies of these particles have been done in aqueous suspension. Here the equilibrium structure of the surface layer of the particles has been investigated by dynamic light scattering and by small‐angle X‐ray scattering. Results deduced from the flow behavior of the particles in dilute solution can directly be derived from static data. Very recent data refer to the interaction of the spherical polyelectrolyte brushes with solid interfaces. It is demonstrated that particles bearing positively charged polyelectrolyte chains interact strongly with negatively charged surfaces. The strong interaction that is directly evident from AFM studies can be used to generate 2D networks of the particles on the surface.

‘Nano-tree’—type spherical polymer brush particles as templates for metallic nanoparticles

“…Using this method, the bottlebrush chains are affixed to colloidal poly(styrene) sphere by a 'grafting from' technique [30][31][32]. The poly(ethylene oxide) (PEO) macromonomer has recently been used repeatedly to prepare defined comb-or star-like polymers [33,34], or as reactive stabilizer to prepare well-defined polymeric microspheres [35,36].…”

Characterization methods of polymer core–shell particles

“…The application of efficient contrast variation does not assure the visualization of single chains by SAXS and SANS, which are involved in the particle diameter obtained by DLS (Fig. 12) [95].…”

Fabrication and morphological evolution of inverse core/shell structural latex particles of poly(vinyl acetate)/polystyrene by maleic anhydride grafting

“…Significant advances on various methods, such as grafting [18][19][20], interpenetrating polymer network [21,22] and ionic bonding [23], have been reported as potential manufacturing approaches for amphiphilic CS latex particles. Among these methods, grafting is one of the most attractive experimental means to fabricate CS latex particles because it can introduce intermediate coupling monomer onto the core particle surface and generate new reactive sites [24][25][26][27][28]. These new sites can react with shell monomer and form a stable polymer shell layer.…”