Dispersion onto polystyrene surfaces

Polystyrene latex particles were coagulated by the addition of Ba(N03)2. The number of dispersed particles deposited onto a planar polystyrene surface was determined 15 min after the addition of salt by optical microscopy. The light microscope does not permit the aggregation of the deposited particles to be determined subsequent examination by the electron microscope gives this information. Clint et al. obtained the following results ... 

If polymer chains are attached onto the surface of particles they hinder aggregation and provide a degree of steric stability. The polymer chains must extend sufficiently into the solution, preventing approach of particles and hindering aggregation. This form of stability is especially useful in organic dispersions where electrostatic stabilization is not possible. An example is polystyrene particles with poly(ethylene oxide) chains terminally attached. This is shown in Fig. 5. 

Structures of surfactants suitable for insoluble films containing proteins are shown in Fig. 2. The films can be cast onto solid surfaces from aqueous vesicle dispersions prepared by sonication [24,25] or from solutions in organic solvents [11,19]. Films containing proteins have also been prepared from composites of bilayer-forming ionic surfactants with ionic polymers of opposite charge (Fig. 2). Examples include polystyrene sulfonate [24] or the ionomer Nafion with DDAB (cf. Fig. 2) [27]. 

When the composite-matrix is formed with a polystyrene solution as a dispersion medium, the self-assembly of silica particles is influenced by the adsorption of macromolecules on their surface. During adsorption, both solitary macromolecules and their aggregates transfer simultaneously onto the adsorbent surface. Depending on solution concentration, not only the conformation of adsorbed molecules but also the number and size of macromolecular aggregates in the solution change on adsorption. This leads to the formation of complex-shaped structures, which are linked by a system of nonvalent interactions and consist of polymeric-inorganic blocks[8,14] this is of interest in the preparation of a nanostructured medium (polystyrene-silica gel) as a precomposite for the fabrication of carbon structures in a matrix of silica particles. 

Similarly, Lan et al. [7] developed a one-step microfluidic method for fabricating nanoparticle-coated patchy particles. A coaxial microfluidic device was employed to produce Janus droplets composed of curable phase and non-curable phase. The results showed that nanoparticles were dispersed either in the continuous fluid or the non-curable phase fluid. The nanoparticles (30 nm or 300-500 nm) were adsorbed onto the interface between these phases, and the curable phase was solidified by UV-irradiated polymerization. Thus, the patchy microparticles asymmetrically coated by nanoparticles were synthesized. They also employed Si02, TS-1, and fluorescent polystyrene nanoparticles as the coating materials to demonstrate the validity of the method. The microfluidic approach exhibited excellent controllability in morphology, monodispersity, and size for the nanocomposites. The morphology of the particles could be controlled from less than a hemisphere to a sphere by adjusting the flow rate ratio of the two dispersed phases. The method can be applied to other nanoparticles with specific surface properties. 

Cast film n. Eilm produced by pouring or spreading a solution, hot melt, or dispersion of plastic material onto a temporary carrier - typically a polished metal roll, hardening the material by suitable means, and stripping the solidified film from the surface. Cellulosic, polystyrene, and vinyl films are often produced in this manner. 

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