Cationic polystyrene latex particles

Fig. 2. Adsorption isotherms of oligonucleotide onto cationic polystyrene latex particles. Samples were mixed and incubated for 2 h at 20°C, 10 2 ionic strength at a given pH [24]...

Pig. 24. Log W against N-/(N + N ) for mixtures of an anionic polystyrene latex (particle radius = 26 nm) and a cationic polystyrene latex (particle radius = 22 nm). N and N = the number coocentration of the cationic and anionic lattices, respectively. Sodium chloiide concentration = 10 mol dm . ... 

Ganachaud, R, Mouterde, G., Delair, T., Elaissari, A., and Pichot, C. 1995. Preparation and characterization of cationic polystyrene latex particles of different aminated surface charges. Polym. Adv. Technol. 6 480-8. 

Serizawa and Akashi [95] analyzed the monolayer adsorption of polystyrene latex particles with cationic polyvinylamine grafted on their surface, while Serizawa et al. [96,97] used commercial anionic latex particles. Both types of particles were adsorbed on polyelectrolyte-coated substrates previously prepared by alternating adsorption of cationic and anionic polyelectrolytes such as polyallylamine hydrochloride (PAH) and polystyrene sulfonate sodium salt (PSS) according to the method described by Decher [164]. Using... 

Figure 9. Diagram illustrating the effect of anionic, cationic, and nonionic surfactants on anionic polystyrene latex particles...

Figure 14. Changes in stability of an anionic polystyrene latex (particle diameter = 52.7 nm) admixed with a cationic latex (particle diameter = 43.4 nm). N+ and N. = the number concentration of the cationic and anionic latices, respectively (-A-) 10 3 mol dm 3 sodium chloride solution (-O-) 2 X 10 3 mol dm 3 sodium...

FIGURE 12.28 The reduction adsorbed amount of nucleic acids onto high cationic polystyrene latexes and low cationic poly(NIPAM) microgel particles as a function of pH at 20°C and M ionic strength. (From Ganachaud, F. et ah, Langmuir, 13, 701, 1997. With permission.)... 

Fig. 2 TFFDSEM images of various anionic polymer latexes of different sizes. From left to right poly(vinylidene chloride) latex of 116nm, and polystyrene particles of 180, 320, tind 696 mn in diameter, assembled onto a large cationic polystyrene latex of 2170 nm via heterocoaguladon in 0.5 mM KCl background electrolyte. Images reproduced from Fig. 7 from [20]...

Fig. 5 SEM photographs of cationic polymer latex particles heterocoagulated onto the surface of crosslinked polystyrene microspheres driven by the hydrophobic effect, against increasing NaQ concentrations. Hard poly[styrene-co-(methacryloyloxyphenyl-dimethylsulfonium methylsul-fate)] particles at (a) 0.5, (b) 50, and (c) 200 mM of NaCl. Soft poly[styrene-co-(butyl acrylate)-co-(methacryloyloxyphenyldimethylsulfonium methylsulfate)] latex particles at (d) 0.5, (e) 50, and (f) 200 mM of NaCl...

Cationic surfactants can reverse the charge on polystyrene latex particles which are initially negatively charged [17,18]. One can expect the same principles to... 

Amalvy, J. L, Unali, G. F., Li, Y, Granger-Bevan, S., Aimes, S. P, Binks, B. P, Rodrigues, J. A., and Whitby, C. P. 2004. Synthesis of sterically stabilized polystyrene latex particles using cationic block copolymers and macromonomers and their application as stimulus-responsive particulate emulsifiers for oil-in-water emulsions. Langmuir 20 4345-4354. 

Figure 1.11 Kaolin clay, used as filler in papermaking, (a) Bare clay particles (b) clay fully coated by cationic polystyrene latex (130 nm diameter). Scale bars 10 and 1 xm, respectively.

In the same year, Fulda and Tieke [75] reported on Langmuir films of monodisperse, 0.5-pm spherical polymer particles with hydrophobic polystyrene cores and hydrophilic shells containing polyacrylic acid or polyacrylamide. Measurement of ir-A curves and scanning electron microscopy (SEM) were used to determine the structure of the monolayers. In subsequent work, Fulda et al. [76] studied a variety of particles with different hydrophilic shells for their ability to form Langmuir films. Fulda and Tieke [77] investigated the influence of subphase conditions (pH, ionic strength) on monolayer formation of cationic and anionic particles as well as the structure of films made from bidisperse mixtures of anionic latex particles. 

These applications require a good knowledge of the nature and magnitude of interactions between nucleic acids and polymer particles. To that purpose, many systematic studies were carried out by different authors and in this lab on the adsorption behavior of various nucleic acids onto various type latex microspheres, mostly cationic and anionically-charged polystyrene or hydrophilic (i.e. poly[N-isopropylacrylamide]) latex particles. 

The first reported work on the adsorption of ODNs onto charged colloids revealed marked affinity differences between sulfate- and amino-containing polystyrene latexes. In fact, low affinity has been observed for sulfated polystyrene particles, whereas high affinities are exhibited in the case of cationic (amine and amidine) polystyrene latexes (Fig. 2). 

Nagai and coworkers reported a study of heterocoagulation driven by the hydrophobic effect of cationically charged hard poly[styrene-C( -(methacryloy-loxyphenyl-dimethylsulfonium methylsulfate)], or soft poly[styrene-co-(butyl acrylate)-co-(methacryloyloxyphenyl-dimethylsulfonium methylsulfate)] latex particles of ca. 220-240 nm in diameter onto neutral microspheres of crosslinked polystyrene (8.5[im in diameter) [37]. A separate study on the small cationic latex particles showed that their interface was hydrophobic, as the cationic surfactant cetyltrimethylammonium bromide (CTAB) adsorbed onto the surface, clearly driven by a hydrophobic effect [38]. The assembly of the cationic latex particles onto the larger microspheres was studied against increasing NaCl concentrations, which influenced the packing patterns from individually spaced to clusters (see Fig. 5). 

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