Aggregation reversible

Block copolymers in a selective solvent, ie., a good solvent for one block but a precipitant for the other, behave like typical amphiphiles. The copolymer molecules aggregate reversibly to form micelles in a manner analogous to the aggregation of classical surfactants. Our block copolymers are very amphiphilic in the sense described above and form well-defined micelles in a wide range of selective solvents. In solvents for polystyrene, the polystyrene block is located in the micelle corona, while the modified block is hidden in the micelle core. 

Actin, the most abundant protein in eukaryotic cells, is the protein component of the microfilaments (actin filaments). Actin occurs in two forms—a monomolecular form (C actin, globular actin) and a polymer (F actin, filamentous actin). G actin is an asymmetrical molecule with a mass of 42 kDa, consisting of two domains. As the ionic strength increases, G actin aggregates reversibly to form F actin, a helical homopolymer. G actin carries a firmly bound ATP molecule that is slowly hydrolyzed in F actin to form ADR Actin therefore also has enzyme properties (ATPase activity). 

Osseo-Asare, K. 1991. Aggregation, reversed micelles and microemulsions in liquid-liquid extraction The tri-n-butyl phosphate-diluent-water-electrolyte system. Adv. Colloid Interface Sci. 37 123-173. 

Conpared to human platelets, the fimctional responses of animal platelets to TP receptor agonists are quite varied. Platelets fh)m some species, such as cats, guinea pigs and rabbits, were repotted to aggregate irreversibly when stirred with sodium arachidonate or 9,ll-azo-PGH2, while sheep and dog platelets feiled to aggregate under the same conditions (74,172). Horse platelets aggregated reversibly in response to arachidonate... 

As distinct from uncharged droplets, flocculation in the range of micrometer-sized droplets is possible. As seen in Fig. 9, even rather large droplets (4 pm) aggregate reversibly if file electrolyte concentration is lower than (1-5) X10 M and the Stem potential is higher than 25 mV. For smaller droplets the domain of flocculation will extend while the domain of coagulation will shrink. For submicrometer droplets, flocculation takes place even at high electrolyte concentrations (0.1 M). 

Figure 4.6 Calculated energy profiles of DLVO interactions as a function of the distance between particle surfaces, (a) Surfaces repel strongly coUoidal particles remain stable, (b) Surfaces come into stable equilibrium if the secondary minimum is deep enough colloids then aggregate reversibly, (c) The interaction curve approaches the pure van der Waals curve and colloids coagulate irreversibly.

As mentioned above, dilute solutions of copolymers in solvents that are good for both components exhibit similar behaviour to homopolymer chains. However, in a selective solvent, whereby the medium is a good solvent for one component, say A, and a poor solvent for the second component B, one part of the amphipathic block or graft separates as a distinct phase, whereas the other stays in solution. The insoluble portion of the amphipathic copolymer will aggregate reversibly to form micelles. It is believed that the polymeric micelles are spherical [4]. The critical micelle concentration of these block and graft copolymers is usually very low. 

In this study we realize microemulsion-based gels using polyacrylamide. These nanogels have the ability to aggregate reversibly for the change of the temperature. With... 

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