Fluorescent Hard-Sphere Polymer Colloids for Confocal Microscopy

Campbell, Andrew I.; Bartlett, Paul

doi:10.1006/jcis.2002.8669

Cited by 65 publications

(77 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We used sterically stabilized polymethyl methacrylate colloids of a = 650 (big) and 230 nm (small) radius and polydispersity 5%, labelled with rhodamine 21 and 1,1 dioctyadecyl-3,3,3,3-tetra methyl indocarbocyanine 22 respectively. We used polystyrene with M w = 3.0 × 10 7 , which implies a polymer size of 164 nm, and a polymer-colloid size ratio of around 0.25 for a = 650 nm and 0.7 for a = 230 nm in a theta solvent 23 .…”

Section: Methods Experimentalmentioning

confidence: 99%

Bridging length scales in colloidal liquids and interfaces from near-critical divergence to single particles

2007

View full text Add to dashboard Cite

Boiling and condensation are among the best recognized phase transitions of condensed matter. Approaching the critical point, a liquid becomes indistinguishable from its vapour, the interfacial thickness diverges and the system is dominated by long-wavelength density fluctuations 1 . Long wavelength usually means hundreds of particle diameters, but here we consider the limits of this assumption, using a mesoscopic analogue of simple liquids, a colloid-polymer mixture 2,3 . We simultaneously visualize both the colloidal particles and near-critical density fluctuations, and reveal particle-level images of the critical clusters and liquid-gas interface. Surprisingly, we find that critical scaling does not break down until the correlation length approaches the size of the constituent particles, where there is a smooth transition to non-critical classical behaviour. Our results could provide a framework for unifying the disparate particle and correlation length scales, and bring new insight into the nature of the liquid-gas interface and the limit of the critical regime.Among the simplest pictures of two different phases is that of a magnet, whose sites can only point up or down, and do so depending solely on their neighbours. This Ising model in fact describes a general class of phase transitions 1 , from the original ferromagnetic transition in magnets to phase separation in alloys, binary liquids, emulsions and polymers, and the liquidgas transition in simple liquids and colloid-polymer mixtures. Although we shall consider the latter two cases, this work has implications for many systems that belong to the same universality class. Close to the critical point, many physical properties such as the bulk correlation length, ξ B , are described by simple scaling, such as ξ B = ξ 0 B ε −ν , where ξ 0 B is the bare correlation length (or critical amplitude) and ε = (T − T C )/T C is a reduced temperature where T is the temperature and T C is the critical temperature. The critical exponent ν = 0.5 according to mean-field theory, and very close to the critical point there is a crossover to ν = 0.63, 'three-dimensional (3D) Ising universality' 4 . We shall refer to the entire scaling regime, both mean field and 3D Ising as the critical region. Although criticality is well understood, the point at which it breaks down has so far received relatively little attention. Conventional theory of critical phenomena assumes a large separation in length scales, that is, that the correlation length is decoupled from other length scales. This length-scale separation lies at the heart of critical universality, implying that the microscopic details are irrelevant. Whereas length-scale coupling has been considered in complex fluids with much longer length scales, such as polymer 5 and ionic 6 solutions, we consider here a more general limit: the case that the correlation length approaches that of the constituent particles. Although it is difficult to approach this limit experimentally in molecular systems, a colloidpolymer mixture provides...

show abstract

Section: Methods Experimentalmentioning

confidence: 99%

Bridging length scales in colloidal liquids and interfaces from near-critical divergence to single particles

2007

View full text Add to dashboard Cite

show abstract

“…[ 39,40] For example, Hu and Larson incorporated a lipophilic dye, initially dissolved in the polymerization medium, into the core of PMMA latex particles stabilized by a PHSA-graft PMMA copolymer. [40] In a second case, fluorescent monomers were prepared in a first instance and copolymerized in the dispersion polymerization process with MMA and methacrylic acid (MA).…”

Section: Fluorescent Latex For Confocal Microscopy Studiesmentioning

confidence: 99%

“…Although the original report was found in the patent literature, the work by Antl et al [38] has been taken as reference in most of the academic publications. [39,41,42,57,58] Using this approach, PHSA homopolymer ( Figure 6) was firstly prepared by polycondensation of 12-hydroxy stearic acid in toluene, usually in the presence of a sulphonic acid catalyst, such as methane sulfonic acid. To achieve sufficient conversion and avoid hydrolysis (i.e.…”

Section: Stabilizer Synthesismentioning

confidence: 99%

“…The polymerization is thermically initiated (80°C) and kept under an inert atmosphere at all times, following the procedure of Antl et al [38] and subsequent research reports. [39,41,42,58] Cairns et al [57] also reported a seeded polymerization which involves the early formation of seeded latex and a subsequent slow continuous introduction of a feed solution. After the latex formation is complete (typically 2 hours), and in order to prevent possible desorption of stabilizer from the latex particle surface, the PHSA-g-PMMA-PGMA copolymer is chemically reacted to the particle surface (second step).…”

Section: Using Phsa-g-pmma-pgmamentioning

confidence: 99%

“…Several examples used a mixture of solvents as the dispersing medium: hexane/high boiling hydrocarbon fraction [38], petroleum ether/dodecane (40/60) [57] or hexane/dodecane [39,42,58,59]. No noticeable difference was found between these reaction mixtures, possibly because the solvency of the polymer formed did not vary significantly across this range of solvent mixtures.…”

Section: Solvent Considerationmentioning

confidence: 99%

See 2 more Smart Citations

Dispersion polymerization in non-polar solvent: Evolution toward emerging applications

Richez

Yow

Biggs

et al. 2013

Progress in Polymer Science

View full text Add to dashboard Cite

Currently, there is a resurgence of interest in the preparation of monodisperse, size-controlled latex particles in non-polar solvents by the dispersion polymerization technique. This technique has great potential for manufacturing bespoke latex particles for emerging applications such as the use of latex particles in electrophoretic displays, where one of the numerous requirements is that the particle systems be suspended in low dielectric constant, non-polar solvents. This article reviews the academic literature around the typical monomers used in non-polar dispersion polymerization. It briefly introduces the origin of the technique and the initial seminal work carried out in this area. It also describes how such particles have been used in the past as model colloids for academic purposes and provide recent examples where dispersion polymerization is used to create novel functional particles. Subsequently, the article provides a thorough knowledge basis for each monomer used in non-polar dispersion polymerization, with a focus on the evolution of the technique, including progress in controlling the final particle characteristics and in designing novel effective stabilizers. Finally, a brief review on the use of the technique to prepare well-controlled latex particles in supercritical fluids is also presented.

show abstract

Confocal Fluorescence Microscopy

Lavrentovich

2012

Characterization of Materials

View full text Add to dashboard Cite

This article describes basic approaches to image materials by means of optical microscopy with fluorescence markers. The fluorescence microscopy is used to image materials in which the contrast cannot be achieved by light absorption, scattering, or birefringence. The fluorescence microscopy benefits greatly from a confocal mode of observation that eliminates signal coming from outside the small region of sample that is probed by a tightly focused laser beam. By scanning the focused laser beamthrough the sample, one obtains a 3D map of density of fluorescing molecules staining the sample. This technique is called confocal laser scanning microscopy (CLSM). By using fluorescent markers of anisometric shape and a polarized laser beam, one can produce 3D images of orientationally ordered materials such as liquid crystals. In this technique, called a fluorescent confocal polarizing microscopy (FCPM), the signal depends on the angle between the transition dipole of the dye and the polarization of probing light. Recent advances in the development of fluorescent markers that can be controllably switched between the bright state and the dark state lead to revolutionary development of far‐field optical microscopy with resolution well below the diffraction limit.

show abstract

Fluorescent Hard-Sphere Polymer Colloids for Confocal Microscopy

Cited by 65 publications

References 15 publications

Bridging length scales in colloidal liquids and interfaces from near-critical divergence to single particles

Bridging length scales in colloidal liquids and interfaces from near-critical divergence to single particles

Dispersion polymerization in non-polar solvent: Evolution toward emerging applications

Confocal Fluorescence Microscopy

Contact Info

Product

Resources

About