Polystyrene colloid particles

Chad E. Reese, Carol D. Guerrero, Jesse M. Weissman, Kangtaek Lee, and Sanford A. Asher Synthesis of highly charged, monodisperse polystyrene colloidal particles for the fabrication cf photonic crystals, J. Colloid Interface Sci., 232 (2000) 76-80... 

Figure 15 The 450 nm polystyrene colloidal particles were ordered to form the colloidal crystal under 12 V electric field across the electrode gap 7 pm. The scale bar is 100 pm. the dark area is the air bubble. Reproduced with permission from T. Gong, D. Wu, and D. M. Marr, Langmuir 19(2003)5967.

Electrophoresis measurements provide a qualitative indication of the assembly of polymer multilayers on colloids [49,50], The -potential as a function of polyelectrolyte layer number for negatively charged polystyrene (PS) particles coated with poly(diallyldimethylam-monium chloride) (PDADMAC) and poly(styrenesulfonate) (PSS) are displayed in Figure... 

Figure 6.5. Experiments involving mimics of sporopollenin (the principal component of spore walls] demonstrate that patterns very similar, if not identical to those of natural spores and pollen, can be produced from mixtures containing colloidal particles. All scales refer to bar in (a. (a Spore-like structures of polystyrene particles and particle aggregates formed around a droplet of hydrocarbon. Scale = 10 p.m. (b A broken structure like that shown in (a. Scale =...

Recently it has been reported that even colloidal particle suspensions themselves, without added polymers, can form dissipative structures. Periodic stripes of colloidal particles (monodisperse particles of diameter 30 nm and 100 nm, respectively) and polystyrene particles (monodisperse diameters from 0.5 to 3 pm) can be formed from dilute aqueous suspensions. The stripes are parallel to the receding direction of the edge of the suspension droplet and thus indicate that a fingering instability... 

The sorbents were hydrophobic Teflon, hydrophobic polystyrene (PS), and hydrophilic silica. These sorbents were negatively charged colloidal particles having smooth surfaces. In adition, PS particles at the surface of which oligomers (8-mers) of ethylene oxide ((EO)8) were grafted at a... 

It is postulated that the main thermodynamic driving force for particle adsorption at the liquid-liquid interface is the osmotic repulsion between the colloidal particles and hydrophilic starch polymer molecules. This leads to an effective depletion flocculation of particles at the boundaries of the starch-rich regions. At the same time, the gelatin has a strong tendency to adsorb at the hydrophobic surface of the polystyrene particles, thereby conferring upon them some degree of thermodynamic... 

Figure 8.14 CLSM images showing the initial development of the microstructure of a phase-separated mixed biopolymer system (25.5 wt% sugar, 31.4 wt% glucose syrup, 7 wt% gelatin, and 4 wt% oxidized starch pH = 5.2, low ionic strength) containing 0.7 wt% polystyrene latex particles (d32 = 0.3 pm). The sample was quenched from 90 to 1 °C, held at 1 °C for 10 min, heated to 40 °C at 6 °C min-1, and observed at 40 °C for various times (a) 2 min, (b) 4 min, (c) 8 min, and (d) 16 min. White regions are rich in colloidal particles. Reproduced from Firoozmand et ai (2009) with permission.

FIG. 13.4 Stereo pairs of colloidal dispersions generated using computer simulations, (a) Polystyrene latex particles at a volume fraction of 0.13 with a surface potential of 50 mV. The 1 1 electrolyte concentration is 10 7 mol/cm3. The structure shown is near crystallization. (The solid-black and solid-gray particles are in the back and in the front, respectively, in the three-dimensional view.) (b) A small increase in the surface potential changes the structure to face-centered cubic crystals. (Redrawn with permission from Hunter 1989.)... 

Fig. 37 Linear chain formation of DNA-coated paramagnetic polystyrene colloids with the different self-protection schemes displayed in Fig. 33. By using an external magnetic field, DNA-functionalized particles were brought together into linear chains, after which the temperature was lowered below the association temperature for beads, and the field turned off. (a) Representative microscopy picture of the resulting chain structures immediately after switching off the magnetic field, (b-d) Chains after 1 h at the specified temperature for particles functionalized with sticky end sequences able to form both loops and hairpins (b, c) or only loops (d). The degree of aggregation of chains in (d) is intermediate between the unprotected, branched chains in (b) and the perfectly linear, protected chains in (c). Adapted with permission from [157]...

We demonstrated how ordered lines of colloidal polystyrene particles can be achieved by a simple dip coating process [70], We used wrinkles produced via a stretch retraction process of a glassy polyelectrolyte multilayer film mounted on a PDMS substrate. Here, the template was dipped into a colloidal particle suspension with the orientation of the wrinkle s grooves with the withdrawing direction of dipping as the sketch in Fig. 11 indicates. 

In the following, we introduce the buildup of more complex surface patterns by TASA of colloidal particles on the wrinkled surfaces. We find that the process is rather versatile and can be applied to various particle types like silica particles, gold particles, polystyrene particles, and bionanoparticles like TMV particles. For the latter, we find that even spin-coating of wrinkled substrates results in large range ordering of TMV particles. 

Recent experimental studies (1-3), on systems of sterically stabilized colloidal particles that are dispersed in polymer solutions, have highlighted the role played by the free polymer molecules. These experiments are particularly relevant because the systems chosen are model dispersions in which the particles can be well approximated as monodisperse hard spheres. This simplifies the interpretation of the data and leads to a better understanding of the intcrparticle forces. DeHek and Vrij (1, 2) have added polystyrene molecules to sterically stabilized silica particles dispersed in cyclohexane and observed the separation of the mixtures into two phases—a silica-rich phase and a polystyrene-rich phase—when the concentration of the free polymer exceeds a certain limiting value. These experimental results indicate that the limiting polymer concentration decreases with increasing molecular weight of... 

Fig. 1. Interaction potential between two colloidal particles as a function of the reduced centre-to-centre separation R = r/2a, where a is the radius of the particles. Curve 1, steric repulsion due to the adsorbed layer (Vs) curve 2, attraction due to the free polymer (Vd) curve 3, van dcr Waals attraction (X7.,) curve 4, sum of the contributions given by curves 1—3. System polvisobutene-stabilized silica particles and polystyrene (free polymer) in cyclohexane at 308 K. Molecular weight of the free polymer = 82,000, volume fraction of polystyrene, 0 = 0.02, a = 48 nm, thickness of the adsorbed layer 6 = 5 nm, x = 0.5 for polystyrene—cyclohexane, x, = 0.47 and xs = 0.10 for polyisobutene— cyclohexane, AjkT 4.54 and v = 0.10.

The sorbents were hydrophobic Teflon and hydrophobic polystyrene (PS). These sorbents were supplied as negatively charged colloidal particles having smooth hydrophobic surfaces. In addition, PS particles at the surface of which oligomers (8-mers) of ethylene oxide ((EO)8) were grafted at a density of one (EO)g-moiety per 2.5 nm2, were used. Because of the water-solubility of EO, these flexible (EO)8 oligomers reach out from the surface into the aqueous solution causing a hairy sorbent surface. A more detailed description of these sorbent materials is described elsewhere.30,31... 

FIG. 12 Pattern of light scattered from a single layer of colloidal particles in the disordered phase. The particles are polystyrene spheres, of diameter 2 /glass plates. Except for the contribution of the form factor P(k), which depends on the scattering angle, and normalization and geometrical factors, this picture shows directly the static structure factor of the system. 

Fig. 14.9. Normalised force (F/R R is the particle radius) vs piezo displacement plot (retraction) for a polystyrene colloid probe in 0.01 M NaCI at pH 8.0. (a) Conventional polyethersulphone membrane, (b) Modified mixed polymer membrane.

---