Polymer droplet

The spreading rate of a polymer droplet on a surface has been measured (363,364). The diffusion constant was at least an order of magnitude smaller than that of the bulk. The monomer—surface friction coefficient for polystyrene has been measured on a number of surfaces and excellent... 

Emulsion Polymerization. Emulsion and suspension reactions are doubly heterogeneous the polymer is insoluble in the monomer and both are insoluble in water. Suspension reactions are similar in behavior to slurry reactors. Oil-soluble initiators are used, so the monomer—polymer droplet is like a small mass reaction. Emulsion polymerizations are more complex. Because the monomer is insoluble in the polymer particle, the simple Smith-Ewart theory does not apply (34). 

Figure 11.2 (a) Microscope image of Benard from Ref 33). (b) Two microscope snapshots convection cells (indicated by the circle in the of an evaporating polystyrene solution on silicon upper left corner) and tears ofwine (indicated wafer. The time between the two frames is by the white arrows) in an evaporating approximately 100 ms. The polymer droplets... 

Figure 11.3 Hierarchical pattern of cyanine-dye J-aggregates. Dye molecules form strongly fluorescent nanoscale J-aggregates J-aggregates arrange at the rim of the micrometer-sized polymer droplet droplets arrange in a regular mm-sized two-dimensional array (adapted from Ref 39).

Recently, we explored the effect of molecular weight on the pattern and employed post-dewetting processes to alter the shape of the dewetted polymer droplets. Since the viscosity of a polymer solution is nonlinear with respect to concentration and also strongly dependent on polymer weight, we expected a drastic effect. Figure 11.4... 

Figure 11.6 Scanning electron micrographs of a dewetted polymer droplet before and after solvent treatment. Viewing angle is 45° and the scale bar is 1 Xm.

Fig. 6. Schematic representation of macroporous PHEMA hydrogel sponges. Interstitial spaces between polymer droplets create a macroporous structure 1-20 pm in size, whereas the polymer network creates a 1-100 nm mesh size in the polymer phase.

The polymerization of the gaseous monomer actually takes place in the polymer droplets, not in the gas phase ... 

These are highly combustible and easily ignited. The natural reaction to a combusting claw, shaking the hand violently, is likely to distribute burning polymer droplets broadcast. Not advised in laboratories. 

L. Wagner, Molecular dynamics simulations of polymer droplets, Phys. Rev E 51, 499-503 (1995). 

During the last years ROMP has been developed to generate self-healing polymers. In these polymers droplets of dicyclopentadiene and of Grubbs-catalyst are incorporated. When the polymer cracks the droplets burst open, the catalyst comes into contact with the monomer and the plastic ideally heals itself [111]. This methodology is still far from application but it does indicate the power of ROMP. 

Functional polymers have been dispersed in water by the spontaneous emulsification (or nanoprecipitation ) method [35, 36]. Such method consists in mixing a polymer solution in acetone to a large amount of water. Complete dissolution of acetone in water takes place readily and leaves the polymer as a supersaturated solution in water. The polymer forms a colloidal suspension upon precipitation. Thereafter, acetone is evaporated under reduced pressure. The resulting emulsion is made of nanometric polymer droplets in the range of 100 nm to 1 pm in the case of... 

A latex has basically two parts, a dispersed phase (polymer particles) and the continuous phase (the water the liquid in which the polymer droplets are dispersed), the process is usually referred to as emulsion... 

L. Wagner, Effect of Substrate Corrugation on the Spreading of Polymer Droplets, Phys. Rev. E 52 (1995) 2797-2800. 

The movement of the pharmaceutical industry away from volatile solvents for coating applications coupled with advancements in coating equipment design led to an increase in the popularity of latex and pseudolatex coating systems. Latexes and pseudolatexes are both colloidal dispersions of polymer droplets in a continuous aqueous phase, the difference between them being that latex systems are formed by emulsion polymerization... 

Among a large number of small polymer droplets, each of volume v, the fraction of droplets which contain exactly z heterogeneities of the kind "A" that usually induce crystallization follows a Poisson distribution function (45) ... 

Scheme 4.3 Comb polymers interconnecting microemulsion droplets at high polymer/droplet ratio (a) and at low polymer/droplet ratio (b).

W/O/W emulsion with drug loaded diphasic polymer droplets... 

The creation of sufficiendy small polymer droplets as a stable suspension was much more difficult. It was therefore only first in 1959 that similar experiments have been reported for polymers [Frensch et al., 1989] (Table 3.25). 

Figure 3.44. Isothermal homogeneous ciystaUization of finely dispersed polymer droplets as a function of time (a) Linear PE,...

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