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Ionic micelles are typically very affected by the salt concentration. In ionic micelles the monomers are typically fully ionized, but the high electric field strength at the surface of the micelles will cause adsorption of some proportion of the free counter-ions.
The shape and size of a micelle are a function of the molecular geometry of its surfactant molecules and solution conditions such as surfactant concentration, temperature, pH, and ionic strength. The process of forming micelles is known as micellisation and forms part of the phase behaviour of many lipids according to their polymorphism. [5]
Note 1: Usually the chain-ends are ions, although ions can also be located ionic on the monomer molecules, as in an activated-monomer polymerization. Note 2: The ions may also be present in the form of higher aggregates that usually are less reactive than non-aggregated species. Modified from the earlier definition. [1]
In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. [1] [2] [3] There are many forms of polymerization [4] and different systems exist to categorize them. IUPAC definition for ...
A monomer is dispersed or emulsified in a solution of surfactant and water, forming relatively large droplets in water. Excess surfactant creates micelles in the water. Small amounts of monomer diffuse through the water to the micelle. A water-soluble initiator is introduced into the water phase where it reacts with monomer in the micelles.
Propagation proceeds by addition of monomer to the active species, i.e. the carbenium ion. The monomer is added to the growing chain in a head-to-tail fashion; in the process, the cationic end group is regenerated to allow for the next round of monomer addition. [6] General propagation pathway
An example of an ionomer, with carboxylate groups bound to a zinc cation. An ionomer (/ ˌ aɪ ˈ ɑː n ə m ər /) (iono-+ -mer) is a polymer composed of repeat units of both electrically neutral repeating units and ionized units covalently bonded to the polymer backbone as pendant group moieties.
The main chain is formed of silicon and oxygen atoms. The homopolymer polyethylene terephthalate has only one repeat unit. Copolymer styrene-butadiene rubber: The repeat units based on styrene and 1,3-butadiene form two repeating units, which can alternate in any order in the macromolecule, making the polymer thus a random copolymer.