Latex colloid

In mass polymerization bulk monomer is converted to polymers. In solution polymerization the reaction is completed in the presence of a solvent. In suspension, dispersed mass, pearl or granular polymerization the monomer, containing dissolved initiator, is polymerized while dispersed in the form of fine droplets in a second non-reactive liquid (usually water). In emulsion polymerization an aqueous emulsion of the monomer in the presence of a water-soluble initiator Is converted to a polymer latex (colloidal dispersion of polymer in water). 

Rubio-Hernandez F.J., Gomez-Merino A.I., Ruiz-Reina E., Carnero-Ruiz C. The primary electroviscous effect of polystyrene latexes. Colloids and Surfaces A Physicochemical and Engineering Aspects 140 (1998) 295-298. 

Harding, I. H., and T. W. Healy (1985), "Electrical Double Layer Properties of Amphoteric Polymer Latex Colloids", J. Coll. Interf. Sd. 107, 382-397. 

A resistive pulse method of particle sizing was used to detect antibody-antigen binding events at a pore fabricated on a PDMS chip. The pore was typically 7-9 pm long and 1 pm in diameter. Mouse monoclonal anti-streptavidin antibody (0.75-10 pg/mL) was supposed to bind to the surface of latex colloidal particles coated with streptavidin (the antigen). This binding, which caused an increase of 1-9 nm of the particle diameter, was measured by the resistive pulse method [1031],... 

H. Huang, M. Manciu, E. Ruckenstein On the Restabilization of Protein-Covered Latex Colloids at High Ionic Strengths, LANGMUIR 21 (2005) 94-99. 

The present article was stimulated by the recent experimental data on protein-covered latex colloidal systems immersed in various electrolyte solutions NaCl, NaNC>3, NaSCN and Ca(NOg)2, which showed strong specific anionic effects on the restabilization curves.1 In the opinion of Lopez-Leon et al.,1 the above polarization model for double layer/hydration forces could explain only some of their experiments, but not all of them. However, they assumed that at pH = 10 the adsorption of anions was negligible hence specific anion effects could not be predicted by their association with the positive sites of the surface. Furthermore, at pH = 4 they assumed the... 

Several approaches towards the synthesis of hierarchical meso- and macro-porous materials have been described. For instance, a mixture that comprised a block co-polymer and polymer latex spheres was utilized to obtain large pore silicas with a bimodal pore size distribution [84]. Rather than pre-organizing latex spheres into an ordered structure they were instead mixed with block-copolymer precursor sols and the resulting structures were disordered. A similar approach that utilized a latex colloidal crystal template was used to assemble a macroporous crystal with amesoporous silica framework [67]. 

Polymers in the form of latex (colloidal dispersions) acquire a novel quality not observed in bulk or solution and which is due to the strongly developed interface with the aqueous phase, The properties of this interface va ry specifically with the nature of the polymer, the latter varying in a wide range for different latexes and other polymer dispersions. 

Duracher, D., Elaissari, A., and Pichot, C., Characterization of cross-bnked poly (A-isopropybnethacrylamide) microgel latexes. Colloid Polym. Sci., 277, 905, 1999. 

Elimelech M. Indirect evidence for hydration forces in the deposition of polystyrene latex colloids on glass surfaces. J Chem Soc Faraday Trans 1990 86 1623-1624. 

The coagulation-dispersion behavior of aqueous silica sols is central to almost all processes requiring their unique adsorption, dispersion, gelation, and sol-gel properties. Aqueous silica sols are of particular interest in colloid science because their coagulation-dispersion behavior is said to be anomalous , that is, their stability in terms of electrolyte-pH control does not follow the pattern followed by almost all other oxide and latex colloidal materials. This chapter examines aqueous silica sol coagulation effects in light of studies of macroscopic silica-water interfaces and in particular the electrical double layer at such interfaces. 

In Fig. 6, we illustrate some different ways that the core-shell topology could be varied for silica and gold. So far we have considered the two normal core-shell structures. We now focus on the third example the assembly of Au Si02 nanoparticles onto spherical polystyrene latex colloids. The resulting spheres are also essentially different to continuous metal shells grown on colloid templates, which have been reported by Halas and colleagues [17] and by van Blaaderen and coworkers [18]. Such continuous shells display optical properties associated with resonances of the whole shell, and are therefore extremely sensitive to both core size and shell thickness, while in the system presented here... 

The usual result of such variation in the zeta potential with pH and 1 1 electrolyte concentration is that the critical coagulation concentration normally varies with pH as shown schematically by the theory line in Figure 20.4. The critical coagulation concentration increases as the pH is increased above the isoelectric point and peaks at high values as shown. Many examples of these trends are confirmed for oxide and latex colloids for which H ... 

C.O. Oriakhi and M.M. Lerner, Poly(pyrrole) and poly(thiophene)/clay nanocomposites via latex-colloid interaction. Materials Research Bulletin, 30, 723—729 (1995). 

F. Sauzedde, A. Elaissari, C. Pichot, Hydrophilic magnetic polymer latexes. 1. Adsorption of magnetic iron oxide nanoparticles onto various cationic latexes. Colloid Polym. Sci. 277, 846-855 (1999)... 

Where the nanoparticles are reacted directly (rather than being used to catalyze reactions), the achievable sensitivity will depend largely on the quantity of metal attached to each DNA sequence. This has led to the development in label construction illustrated in Fig. 8.1. From the binding of individual particles, researchers have sought techniques to attach assemblies of nanoparticles to a given DNA sequence. As will be described in this chapter, latex colloids provide an ideal base for such assemblies, both as solid supports and as templates for the construction of hollow capsules which can take up nanomaterials. The point of importance is thatthe necessary latex modifications have already been intensively researched for other applications, and so the relevant physical chemistry theory and experimental details are already available. Despite this fact, the use of latex in constructing electrochemical DNA labels is relatively unexplored. 

It is hoped that this chapter has transmitted two general points that it is relatively straightforward to adapt latex colloids for use as electrochemical labels, and that very little has been done in this field up to now. Some possible further directions for research are as follows ... 

Flow Cytometer Lab-on-a-Chip Devices, Fig. 5 Microfabricated Coulter counter (a) scanning electron microscope image of the Coulter counter. The 3.5 pm-deep reservoirs and the inner Ti/Pt electrodes, which control the voltage applied to the pore but pass no current, are only partially shown. The inset shows a magnified view of this device s pore, which has dimensions 5.1 X 1.5 X 1.0 pm, and (b) relative changes in baseline current versus time for a monodisperse solution of 87 nm diameter latex colloids and a polydisperse solution of latex colloids with diameters 460, 500, 560, and 640 nm [5]... 

SPBs can be prepared by surface-initiated ATRP with a variety of core particles, including organic latexes colloids emulsions, shells of shell-cross-linked micelles, and... 

Monodispersed PS latex colloids with aldehyde and acetal functionalities were synthesised by a two-step emulsion polymerisation process. The samples were chosen as the polymeric support to carry out covalent coupling with the antibody IgG anti-C reactive protein. 14 refs. 

Journal of Applied Polymer Science 76, No.ll, 13th June 2000, p.1677-82 CATIONIC LATEX COLLOIDAL BEHAVIOUR AND INTERACTION WITH ANIONIC PULP FIBRES... 

Sukhorukov, A Kornowski, H. Mohwald, M. Giersig, A. Eychmiiller, H. Weller H, Formation of luminescent spherical coreshell particles by the consecutive adsorption of polyelectrolyte and CdTe(S) nanocrystals on latex colloids. Colloid Surface A 2000, 163, 39-44 (c) F. Caruso, Hollow capsule processing through colloidal templating and self-assembly, Chem. Eur. J. 

E. Barouch, Heterocoagulation. VI. Interactions of monodispersed hydrous aluminum oxide sol with polystyrene latex, /. Colloid Interf. Sci. 1980, 76,319-329 (c) K. Csoban, E. PefFerkorn, Perikinetic aggregation induced by chromium hydrolytic polymer and sol,/. Colloid Interf. Sci. 1998, 205,516-527. 

T.W. Healy, A. Homola, R.O. James, R.J. Hunter, Coagulation of amphoteric latex colloids reversibility and specific ion effects. Faraday Discuss. Chem. Soc. 65, 156-163 (1978). doi 10. 1039/dc9786500156... 

Fig. 1.19 Micrographs of latex colloids mixed with HEC by Speiiy [112-114]. Picture reprinted from P. R. Sperry, J. Colloid Interface Sci., 99 97, Copyright 1984, with permission Ixom Elsevier...

What are the limits of the approximated expression Eq. 4 Mainly those due to the mean-field nature of PB. For, say, 99 % of the studied systems, the ions are monovalent, ion-ion correlations in water can be safely ignored, and the standard expression is valid. This is no more the case in presence of multivalent counterions (or monovalent ions in solvent of low e). That opens to the fascinating concept of electrostatic attraction between hke-charged colloids, subject of numerous false analyses, debates, and controversies in the literature for 30 years. Figure 1 presents Monte Carlo (MC) simulations data for the force vs. separation law within the primitive model (two latex colloids and ions in continuous solvent) in presence of counterions of increasing valence. While the PB/DLVO prediction remains everywhere repulsive, the exact MC behavior deviates at intermediate separation and develops an attractive well deeper and deeper as the valence increases above 3. This non mean-field effect is due to the repulsions and correlations among the counterions localized in the intersticial region (discreteness of the condensed layer). The same type of colloidal attraction is responsible for a liquid-gas (concentrated solution-dilute solution) phase separation, observed... 

The Production of Natural Rubber from Hevea brasiliensis Latex Colloidal Properties, Preservation, Purification and Processing... 

---